the position of the thermometer. The one reliable guide for
temperature is the action of the chicks. If they are cold they will
crowd toward the source of heat; if too warm they will wander
uneasily about; but if the temperature is right, each chick will
sleep stretched out on the floor. The cold chicken does not sleep at
all, but puts in its time fighting its way toward the source of
heat. In an improperly constructed or improperly run brooder the
chicks go through a varying process of chilling, sweating and
struggling when they should be sleeping, and the result is puny
chicks that dwindle and die.
The arrangement of the brooder for the sleeping accommodations of
the chicks is important, but this is not the only thing to be
considered in a brooder. The brooder used in the early season, and
especially the outdoor brooder, must have ample space provided for
the daytime accommodation of the chick. In the colony house brooder
such space will, of course, be the floor of the house.
When operating on a large scale it will not pay to buy complete
brooders. The lamps and hovers can be purchased separately and
installed in colony houses which do both for brooders and later for
houses for growing young stock. The universal hover sold by the
Prairie State Incubator people is about as perfect a lamp hover as
can be made.
The cold brooder, or Philo box, as it has been popularly called, is
the chief item in a system of poultry keeping that has been widely
advertised. The principle of the Philo box is that of holding the
air warmed by the chick down close to them by a sagging piece of
cloth. The cloth checks most of the radiating heat, but is not so
tight as to smother the chick. This limits the space of air to be
warmed by the chicks to such a degree that the body warmth is used
to the greatest advantage. That chickens can be raised in these
fire-less brooders, is not in question, for that has been abundantly
proven, but most poultrymen believe that it will pay better,
especially in the North, to give the little fellows a few weeks'
warmth.
Curtis Bros. at Ransomville, N.Y., who raise some twenty thousand
chicks per year, have adopted the following system: The chicks are
kept under hovers heated by hot water pipes for one week, or until
they learn to hover. Then they are put in Philo boxes for a week in
the same building but away from the pipes. The third week the Philo
boxes are placed in a large, unheated room. After that they go to a
large Philo box in a colony house.
To make a Philo house of the Curtis pattern, take a box 5 in. deep
and 18 in. to 24 in. square. Cut a hole in one side for a chick
door, run a strip of screen around the inside of the box to round
the corners. Now take a second similar box. Tack a piece of cloth
rather loosely across its open face. Bore a few augur holes in the
sides of either box. Invert box No. 2 upon box No. 1. This we will
call a Curtis box. It costs about fifteen cents and should
accommodate fifty to seventy-five chicks.
A universal hover in a colony coop or colony house, for which a
Curtis box is substituted, as early in the game as the weather
permits, is the method I advise for rearing young chicks. The lamp
problem we still have with us, but it is one that cannot be easily
solved. Large vessels or tanks of water which are regularly warmed
by injection of steam from a movable boiler, offers a possible way
out of the difficulty. On a plant large enough to keep one man
continually at this work, this plan might be an improvement over
filling lamps, but for the smaller plant it is lamps, or go south.
Rearing young chicks is the hardest part of the poultry business.
There is a lot of work about it that cannot be gotten rid of. Little
chicks must be kept comfortable and their water and feed for the
first few days must needs be given largely by hand. They are to be
early led to drink from the regular water vessels and eat from the
hoppers, but this takes time and patience.
The feeding of chicks I will discuss in the chapter on "Poultry on
the General Farm," and as the same methods apply in both cases, I
will refer the reader to that section.
After chicks get three or four weeks old their care is the simplest
part of the poultry farm work and consists chiefly of filling feed
hoppers and protecting them from vermin and thieves.
Board floor colony houses are used as a protection against rats and
this danger necessitates the protection of the opening by netting
and the closing of the doors at night.
Cockerels must be gotten out of the flocks and sold at an early age.
Those that are to be kept for sale or use as breeding birds should
be early separated from the pullets. Coops for growing chickens,
especially Leghorns, cannot be put among trees, as the birds will
learn to roost in the trees, causing no end of trouble to get them
broken of the habit.
All pullets save a few culls should be saved for laying. They are to
be kept two years. They should lay sixty-five to seventy per cent as
many eggs the second year as the first. They are sold the third
summer to make room for the growing stock.
Twenty-five Acre Poultry Farms.
This section will be devoted to a general discussion of the type of
poultry farms best suited to Section 4 and the southerly portions of
Section 7 as discussed in the previous chapter.
We will discuss this type of farm with this assumption: That they
are to be developed in large numbers by co-operative or corporate
effort. This does not infer that they cannot be developed by
individual effort, and nine-tenths of the operations will remain the
same in the latter case.
Suppose a large tract of land adjacent to railroad facilities has
been found. The land in the original survey should be divided into
long, relatively narrow strips, lying at right angles to the slope
of the land. The farmstead should occupy the highest end of the
strip. For a twenty-five acre or one-man poultry farm these strips
should be about forty rods in width. The object of this survey is to
permit the water being run by gravity to the entire farm.
The first thing is the farmstead, including such orchard and garden
as are desired. This stretches across the entire front end of the
place. The remainder of the strip is fenced in with chicken fence.
The farm is also divided into two narrow fields by a fence down the
center of the strip. This fence, at frequent intervals, has
removable panels.
The year's season we will begin late in the fall. All layers are in
field No. 1 pasturing on rape, top turnips or other fall crops. In
lot No. 2 is growing wheat or rye. As the green feed gets short in
the first lot the hens are let into lot No. 2. Sometime in March the
houses that have been brought up close to the gaps are drawn through
into the wheat field. The feed hoppers are also gradually moved and
the hens find themselves confined in lot No. 2 without any serious
disturbance.
Lot No. 1 is broken up as soon as weather permits and planted in
oats, corn, Kaffir corn and perhaps a few sunflowers. The oats form
a little strip near the coops and watering places and the Kaffir
corn is on the far side. As soon as corn planting is over the farmer
begins to receive his chickens from the hatchery. The brooders are
now placed in the corn field. The object of the corn is not green
food but for a shade and a grain crop.
The chicks are summered in the corn field and the hens in the wheat
or rye. Whether the latter will head up will depend upon the number
of the flock. It will be best to work the houses across to the far
side and let that portion near the middle fence head up. As the old
grain gets too tough for green food strips of ground should be
broken up and sown in oats. The grain that matures will not be cut,
but the hens will be allowed to thresh it out. The straw may be cut
with mower or scythe for use as nesting material.
Sometime in June or early in July a little rape vetch or cow-peas is
drilled in between the rows of corn as on the far side from the
chicken coops. During July or about the first of August, after all
cockerels have been sold, the gates are opened and the pullets are
allowed to associate with the hens. After this acquaintance ripens
into friendship the hen houses are worked back into the pullet lots.
Surplus hens are sold off or new houses inserted as the case may be
until there is room for the pullets in the houses. Each coop is
worked up alongside a house and after most of the pullets have taken
to the houses the coops are removed. The vacant lot is now broken up
and sown in a mixture of fall green crops.
The flock is kept in the corn field until the corn is ripe. The
Kaffir corn and sunflowers are knocked down where they stand and are
threshed by the hens. As soon as the corn crop is ripe the houses
are run back and the corn cut up or husked and the wheat planted in
the corn field.
The next year the lots are transposed, the young stock being grown
in the lot that had the hens the previous year.
If the ground is inclined to be at all damp when the fields are
broken up the plowing is done in narrow lands so as to form a
succession of ridges, on which are placed the coops or houses. The
directions of these ridges will be determined by the lay of the
land--the object being neither to dam up water or to encourage
washing. The location of the ridges are alternated by seasons, so
that the droppings from the houses are well distributed throughout
the soil.
This system with the particular crops found that do best in the
locality, give us an ideal method of poultry husbandry. We have kept
hens and young stock supplied with green food the year round; we
have utilized every particle of manure without one bit of labor. We
have a rotation of crops. We have the benefits to the ground of
several green crops turned under. We have raised one grain crop per
year on most of the ground. We have no labor in feeding and watering
except the keeping of the grain, beef and grit hoppers filled, and
the water system in order.
The number of fowls that may be kept per acre will be determined by
the richness of the soil. The chief object of the entire scheme is
to provide abundant green pasture at all times and to allow the
production of a reasonable amount of grain. With one hundred hens
per acre on the entire tract, and with houses containing eighty hens
each, it will be necessary to set the houses ninety-five feet apart.
This will give the flock a tract of 95 by 330 feet in which to
pasture.
The above estimate with a little land allowed for house, garden,
orchard and a little cow and team pasture, will permit the keeping
of two thousand hens on a twenty-five acre farm. In regions where
grain is to be raised most farmers would want more land. They may
also wish to own a few extra cows, hogs, etc., or to alternate the
entire poultry operations with some crop that will, on such highly
fertilized land, give a good cash profit. Forty acres is a good size
for such uses.
The cost of land when purchased in large tracts in Virginia is very
small, but the cost of clearing is often much more than that of the
land. Twenty-five to fifty dollars an acre should secure such a
tract of land and put it in shape for poultry farming.
The cost of the farm home, etc., will, of course vary altogether
with the taste of the occupant. If they are constructed by a central
company, from five hundred to a thousand dollars should cover the
amount.
The cost of poultry buildings and equipment used on the farm will
depend largely on the efficiency of the labor of construction. If
constructed in large numbers by a central company, the cost would be
reduced, but the company would expect to make a profit on their
work.
A plot laid out for two thousand hens will require in material: 250
rods of fence with 6-ft. netting which should cost about fifty cents
a rod. My estimate of this fence put up would be $150. If the
neighboring field contained no other poultry, a portion of this
fence might be done away with, although its protection against dogs
and strangers may be worth while. Of course, if poultry fields of
different owners lay adjoining, the fence must be used, but the cost
will be reduced one-half.
The next most expensive piece of equipment will be a line of about
eighty rods of 3/4 in. gas pipe and about fifty elbows and
twenty-five galvanized iron pans. The cost of installation will
depend largely on how deep it is necessary to go to get below the
frost line. One hundred and seventy-five dollars should cover cost
of material and by the use of a plow the line ought to be put in for
twenty-five dollars.
The source of water, and the cost of getting a head, will
necessarily vary with the location. The installation of a wind mill
and tank to hold supply for several days, or of a small gasoline
engine, would cost in the neighborhood of one hundred dollars, but
it is a luxury that may be dispensed with if the well is not too
deep.
The houses for the hens, of which there are twenty-five, are
constructed in accordance with some of the plans previously
discussed. The cost should be about twenty-five cents per hen.
At least twice as many brooders as colony coops will be needed as
there are hen houses, but of the lamps and hovers not over
twenty-five will be required, as the chicks soon outgrow the need of
this aid.
This makes a list of equipment required for the keeping of two
thousand layers and their replenishing:
25 acres of farm land, at $50 per acre $1250.00
250 rods of fence 150.00
One farmstead 1000.00
One team, plow and farm implements 300.00
One watering system 300.00
25 hen houses, at $20 500.00
50 colony coops, at $2.50 150.00
25 lamps and hovers, at $5 125.00
--------
$3775.00
[Transcriber's note: "50 colony coops, at $2.50" is $125.00, not
$150. The total should therefore be $3750 rather than $3775. This
was, presumably, a printing error, because the correct total is
used in the further calculations below.]
This is a good, liberal capitalization. The business can be started
with much less. Figured interest at 6 per cent. we have $225.00 per
year.
The upkeep of the plant will be about 15 per cent. on the capital,
not counting land. This equals $375, which, added to interest, gives
an annual overhead expense of $600, which is our first item to be
set against gross receipts.
The cost of operation will involve cost of chicks at hatchery,
purchased feed, seed for ground, and feed for team.
The price of chicks at the Petaluma hatcheries is from six to eight
cents each. We expect to raise enough pullets to make up for the
accidental losses, and to renew bulk of the flock each year. The
number required will, of course, depend upon the loss. This loss
will be much less when the chicks are obtained from a modern
moisture controlled hatchery, than from the box type incubator. I
think a 33 per cent. loss is a liberal estimate, but as I am
treading on unproven ground, I will make that loss 40 per cent.,
which is on a par with old style methods. To replace 1,000 hens,
this will require 3,500 chicks at a cost of about two hundred and
fifty dollars.
Green pasturage throughout the year will materially cut down the
cost of feed. The corn consumed out of the hoppers will be about one
bushel per hen. The beef scrap will also be less than with yarded
fowls, perhaps twenty-five cents per hen. Now, of the corn we will
raise on the land, at least ten acres. This should yield us five
hundred bushels. This leaves fifteen hundred bushels of corn to be
purchased. At the present high rates, this will cost $1,000 which,
added to beef scrap cost, makes an outside feed cost of $1,500. The
seed cost of rye, rape, cow-peas, etc., will amount to about $50 per
annum. For expense of production we have:
Interest and upkeep of plant $600.00
Chicks 250.00
Purchased corn 1000.00
Beef scrap and grit 500.00
Seed 50.00
Team feed 100.00
---------
$2,500.00
This figures out the cost of production at a little more than a
dollar per hen. The income from the place should be about as
follows: Eleven hundred cockerels sold as squab broilers at 40 cents
each, $440.00; four hundred and seventy-five old hens at 30 cents,
$140.00.
The receipts from egg yield are, of course, impossible of very
accurate calculation, for it is here that the personal element that
determines success or failure enters. The Arkansas per-hen-day
figures (see last chapter), multiplied by the average quotation for
extras in the New York market, will be as fair as any, and certainly
cannot be considered a high estimate, as it is only 113 eggs per hen
per year.
Price per doz Income for
Eggs per Extras month from
hen day in New York 2000 layers
---------------------------------------------
January .32 $ .30 $494.00
February .30 .29 404.00
March .62 .22 700.00
April .38 .19 350.00
May .44 .19 429.00
June .42 .18 377.00
July .34 .21 367.00
August .38 .22 429.00
September .21 .25 262.00
October .22 .28 316.00
November .18 .33 267.00
December .15 .32 246.00
---------
Total $4,641.00
The total income as figured will be $5,221. From this subtract the
cost of production, and we have still nearly $3,000, which is to be
combined item of wages and profit. We have entered no labor bill
because this is to be a one-man farm, and with the assistance of the
public hatchery and co-operative marketing association, which will
send a wagon right to a man's door to gather the eggs, it is
entirely feasible for one man to attend to two thousand hens. In the
rush spring season other members of the family will have to turn out
and help, or a man may be hired to attend the plowing and rougher
work.
This is a good handsome income, and yet the above price of the man's
labor--it is only about one dollar per hen, which has always been
the estimated profit of successful poultry keeping. As a matter of
fact, this profit is seldom reached under the old system of poultry
keeping, not because the above gross income cannot be reached, but
because the expenses are greater. Under the present methods, with
the exception of the rearing of the young chicks, one man can easily
take care of three thousand hens. Indeed, practically the only work
in their care is cultivating the ground and hauling around and
dumping into hoppers, about two loads of feed per week.
But, young chicks must be reared, and this is more laborious. For
this reason I advise going into some other industry on a part of the
land, which will not require attention in the young chick season.
One of the best things for this purpose is the cultivation of cane
fruits as blackberries, raspberries and dewberries. The work of
caring for these can be made to fall wholly without the young chick
season. Peaches and grapes for a slower profit can be added, but
spraying and cultivation of these is more liable to take spring
labor. All these fruits have the advantage of doing well in the same
kind of soil recommended for chickens. Young chickens may be grown
around such berry crops and removed to permanent quarters before the
berries ripen. Strawberries would be a very poor crop because their
labor falls in the chick season.
Another plan, and perhaps a better one, is to have about three
fields, and rotate in such a manner that a marketable crop may be
always kept growing in the third field. Any crop may be selected,
the chief labor of which falls between July and the following March.
Late cabbage and potatoes, or celery, will do if the ground is
suitable for these crops. Kale and spinach are staple fall crops.
Fall lettuce could also be grown. If the market is glutted on such
crops, they can be fed out at home. Whenever a field is vacant, have
some crop growing on it, if only for purposes of green manuring.
Never let sandy ground lie fallow.
A modification of the above plans suited to heavier ground, is to
seed down the entire farm to grass. It is then divided into three
fields and provided with three sets of colony houses. Coops are
entirely dispensed with, and cheap indoor brooders are used in the
permanent houses. The pullets stay in these same houses in the same
field until the moulting season of the third year, or until they are
two and a half years old. One field will always be vacant during the
fall and winter season which time may be utilized for fresh seeding.
The difficulty of maintaining a sod will necessitate somewhat
heavier soil than by the previous plan. The houses should be moved
around occasionally, as the grass kills out in the locality. This
plan is a lazy man's way, taking the least labor of any method of
poultry keeping known. It is adapted to the cheaper ground in the
region farthest from market. On the Atlantic seaboard, the more
enterprising man will use the third field for rotation, and sell
some of the fertility of the western grain in the form of a truck
crop.
Five Acre Poultry Farms.
Can a living for a family be made from a five acre poultry farm?
Yes; by individual effort, where the marketing opportunities are
good; by corporate or co-operate effort, any place where the
fundamental conditions are right.
This type of poultry farm is well suited for development near our
large cities, where the cry of "back to the land" has filled with
new hope the discouraged dweller in flat and tenement. No greater
chance for humanitarian work, and at the same time no greater
business opportunity, is open to-day than that of the promotion of
colonies of small poultry and truck farms where the parent colony
not only sells the land, but helps the settler to establish himself
in the business and to successfully market the product. The natural
location for such projects is in the sandy soils of New Jersey,
Delaware, Maryland and Virginia.
We have already discussed the twenty-five acre farm, representing
the largest probable unit for such an enterprise. We will now
discuss the five acre farm which represents the smallest probable
unit.
On the five-acre farm a considerable difference of methods will be
necessary. In the first place, it is to be a horseless farm. All
hauling and plowing must be attended to by the central company, or
the same results could be obtained by a team owned in common by a
small group, say of six farmers, each of whom is to use the team one
day of the week.
A single isolated farmer in a community of farms or market
gardeners, could hire a team by the day as he needed it. I do not
recommend this scheme, however, but would suggest that the single
individual get a larger plot of ground, at least ten acres, and a
team of his own. In the co-operative community the five-acre
teamless farm is entirely feasible.
The tract should be surveyed about twice as long as wide, which, for
five acres, makes it 20 by 40 rods, or 330 by 660 feet. Measure off
a strip one hundred feet back from the road. Fence the remainder of
the tract. Now run a partition fence down the center until we have
come to within twelve rods of the back side. Here run a cross fence.
This gives us three yards of about one and one-half acres each. The
gates are arranged so that one passes through the three yards in a
single trip.
Where the middle partition fence adjoins the front fence, a well is
driven. A water line is run down the partition fence to the rear
yard.
The plot around the house is set in permanent crops, such as
berries, fruit trees, asparagus, rhubarb, etc. Of the other three
yards, at least one is kept in growing marketable crops. Every inch
is cultivated, and crops of the leafy nature, as lettuce, cabbage,
kale and spinach, are chiefly grown, as they utilize the rich
nitrogenous poultry manure to the best advantage, and the waste
portions, or worthless crops, are utilized for the poultry. The
method of supplying the fowls with green food is entirely by
soiling. This means to grow the food in an adjoining lot and throw
it over the fence. The above mentioned crops are all good for the
purpose. Rape, which is not grown for human food, is also excellent.
Kale is one of the very best crops for soiling purposes. It is
planted in the fall and fed by pulling off the lower leaves during
the winter. In the spring the hardened stalks stand at a
considerable height and the field may be used for growing young
chicks, giving shade, and at the same time producing abundant green
feed, without any immediate labor, which means a great saving in the
busy season.
A set of panels or netting stretched on light frames is provided.
They are of sufficient number to set along the longest side of one
of the fields. A strip along the fence, four or five feet wide, can
be planted to sunflowers, corn, rape, kale, or other rank growing
crop and the panels leaned against the fence to protect the young
plants from the hens. In this way the fence rows can be kept
provided with the shade of growing crops, which relieves the
otherwise serious fault of this plan of poultry farming, in that the
hens would be required to live in absolutely barren and sunburned
lots, for we propose to keep five or six hundred hens on one and a
half acres of ground, and no green things could get a start without
protection.
Rotate the houses from field to field as often as the crops allow.
Never permit hens to run in one bare field for more than six months
at a time. Always keep every inch of ground not in use by the
chickens, luxuriant in something green. If you have a crop of
vegetables which are about matured, drill rape or crimson clover
between the rows; by the time the crop is harvested and the hens are
to be moved in, such crops will have made a good growth. The hens
will kill it out but it will be a "profitable killing."
By this system of intensive combination of trucking and poultry
farming, we have a combination which for small capital and small
lands cannot be beaten. The hens should yield better than a dollar
profit per head on this plan; the one and a half acres automatically
fertilized and intensely cultivated, growing two or three crops a
year, should easily double the income.
Twelve hundred dollars a year is a conservative estimate for the net
income from such a plant, and the original investment, exclusive of
residence, will not be over one thousand dollars.
CHAPTER VI
INCUBATION
The differences in the process of reproduction in birds and mammals
is frequently misunderstood. The laying of the bird's egg is not
analogous to the birth of young in mammals.
The female, whether bird or beast, forms a true egg which must be
fertilized by the male sperm cell before the offspring can develop.
In the mammal, if fertilization does not occur, the egg which is
inconspicuous, passes out of the body and is lost. If fertilized, it
passes into the womb where the young develops through the embryonic
stages, being supplied with nourishment and oxygen directly by the
mother.
In the bird, the egg, fertilized or unfertilized, passes out of the
body and, being of conspicuous size, is readily observed. The size
of the egg is due to the supply of food material which is comparable
with that supplied to the mammalian young during its stay in the
mother's womb.
The reptiles lay eggs that are left to develop outside of the body
of the mother, subject to the vicissitudes of the environment. The
young of the bird, being warm blooded, cannot develop without more
uniform temperature than weather conditions ordinarily supply. This
heat is supplied by the instinctive brooding habit of the mother
bird.
Fertility of Eggs
In a state of nature the number of eggs laid by wild fowl are only
as many as can be covered by the female. These are laid in the
spring of the year, and one copulation of the male bird is
sufficient to fertilize the entire clutch. Under domestication, the
hen lays quite indefinitely, and is served by the male at frequent
intervals. The fertilizing power of the male bird extends over a
period of about 15 days.
For most of my readers, it will be unnecessary to state that the
male has no influence upon the other offspring than those which he
actually fertilizes within this period. The belief in the influence
of the first male upon the later hatches by another male is simply a
superstition.
The domestic chicken is decidedly polygamous. The common rule is one
male to 12 or 15 hens. I have had equally good results, however,
with one male to 20 hens. In the Little Compton and South Shore
districts, one male is used for thirty or even forty hens.
By infertile eggs is meant eggs in which the sperm cell has never
united with the ovum. Such eggs may occur in a flock from the
absence of the male, from his disinclination or physical inability
to serve the hens, from the weakness or lack of vitality in the
sperm cells, from his neglect of a particular hen, from
lifelessness, or lack of vitality in the ovule, or from chance
misses, by which some eggs fail to be reached by the sperm cells.
In practice, lack of sexual inclination in a vigorous looking
rooster is very rare indeed. The more likely explanation is that he
neglects some hens, or that the eggs are fertilized, but the germs
die before incubation begins, or in the early stages of that
process. The former trouble may be avoided by having a relay of
roosters and shutting each one up part of the time. The latter
difficulty will be diminished by setting the egg as fresh as
possible, meanwhile storing them in a cool place. The other factors
to be considered in getting fertile eggs, are so nearly synonymous
with the problems of health and vitality in laying stock generally,
that to discuss it here would be but a repetition of ideas.
In connection with the discussion of fertile eggs, I want to point
out the fact that the whole subject of fertility as distinct from
hatchability, is somewhat meaningless. The facts of the case are,
that whatever factors in the care of the stock will get a large
percentage fertile eggs, will also give hatchable eggs and vice
versa. This is to be explained by the fact that most of the
unfertile eggs tested out during incubation, are in reality dead
germs in which death has occurred before the chick became visible to
the naked eye. Such deaths should usually be ascribed to poor
parentage, but may be caused by wrong storage or incubation.
Likewise, it would not be just to credit all deaths after chicks
became visible to wrong incubation, although the most of the blame
probably belongs there.
Likewise, with brooder chicks, we must divide the credit of their
livability in an arbitrary fashion between parentage, incubation,
and care after hatching.
By the hatchability of eggs, we then mean the percentage of eggs set
that hatch chicks able to walk and eat. By the livability of chicks,
we mean the percentage of chicks hatched that live to the age of
four weeks, after which they are subject to no greater death rate
than adult chickens. By the livability of eggs, we mean the product
of these two factors, i.e.: the percentage of chicks at four weeks
of age based upon the total number of eggs set.
As before mentioned, the fertility of eggs bears fairly definite
relation to the hatchability, so likewise the hatchability bears a
relation to the livability of chicks. When poor hatches occur
because of weak germs, as because of faulty incubation, this same
injury to the chick's organism is carried over and causes a larger
death among the hatched chicks.
Moreover, the relation between the two is not the same with all
classes of hatches, but as hatches get poorer the mortality among
the chicks increases at an accelerating rate. The following table
gives a rough approximation of these ratios:
Per cent. of Per cent. of chick Per cent. of egg
Hatchability. Livability. Livability.
100 100 100
90 95 85
80 88 70
70 84 50
60 72 43
50 55 27
40 40 16
30 24 7
20 10 2
10 2 1
These figures are based on incubator data. Eggs set under hens
usually give a hatchability of 50 per cent. to 65 per cent., and
livability of 70 per cent. to 80 per cent. The reason for the
greater livability is that the real hatchability of the eggs is 70
per cent. to 75 per cent., and is reduced by mechanical breakage.
The hatchability of eggs varies with the season. This variation is
commonly ascribed to nature, it being stated that springtime is the
natural breeding season, and therefore eggs are of greater
fertility.
While there may be a little foundation for this idea, the chief
cause is to be found in the manner of artificial incubation, as will
be discussed in a later section of this chapter. The following table
is given as the seasonable hatchability for northern states. This is
based on May hatch of 50 per cent:
January 38 July 40
February 42 August 40
March 47 September 42
April 49 October 43
May 50 November 40
June 46 December 35
Most people have an exaggerated idea of the hen's success as a
hatcher. I have a number of records of hen hatching with large
numbers of eggs set, and they are all between 55 per cent. and 60
per cent. The reasons the hen does not hatch better are as follows:
First: Actual infertile eggs--usually, running about 10 per cent. in
the best season of the year.
Second: Mechanical breakage.
Third: Eggs accidentally getting chilled by rolled to one side of
the nests, or by the sick, lousy or crazy hens leaving the nests or
standing up on the eggs.
Fourth: Eggs getting damp from wet nests, dung or broken eggs; thus
causing bacterial infection and decay.
The last three causes are not present in artificial incubation. From
my observation they cause a loss of 15 per cent. of the eggs that
fail to hatch, when hens are managed in large numbers. This would
properly credit our hens with hatches running from 70 per cent. to
75 per cent., which, for reasons later explained, is not equal to
hatches under the best known conditions of artificial incubation.
The assumption that the hen is a perfect hatcher, even barring
accidents and the inherited imperfection of the egg, is not, I
think, in harmony with our general conception of nature. Not only
are eggs under the hens subject to unfavorable weather conditions,
but the hen, to satisfy her whims or hunger, frequently remains too
long away from the eggs, allowing them to become chilled.
For directions of how to manage setting hens, consult the Chapter on
"Poultry on the General Farm."
The Wisdom of the Egyptians.
Up to the present there have been just three types of artificial
incubation that have proven successful enough to warrant our
attention. These are:
First, the modern wooden-box-kerosene-lamp incubator which is seen
at its best development in the United States.
Second, the Egyptian incubator of ancient origin, which is a large
clay oven holding thousands of eggs and warmed by smouldering fires
of straw.
Third, the Chinese incubator, much on the principle of the Egyptian
hatchery, but run in the room of an ordinary house, heated with
charcoal braziers and used only for duck eggs.
I have no accurate information on the results of the Chinese method,
and as it is not used for hen eggs, we will confine our attention to
the first two processes only.
I do not care to go into detail in discussing makes of box
incubators, but I will mention briefly the chief points in the
development of our present machines.
The first difficulties were in getting lamps, regulators, etc., that
would give a uniform temperature. This now has been worked out to a
point where, with any good incubator and an experienced operator,
the temperature of the egg chamber is readily kept within the
desired range.
These are two principal types of box incubators now in use. In the
earliest of these, the eggs were heated by radiation from a tank of
hot water. These machines depended for ventilation or, what is much
more important, evaporation, upon chance air currents passing in and
out of augur holes in the ends or bottom of the machine.
The second, or more modern type, warms the eggs by a current of air
which passes around a lamp flue where, being made lighter by the
expansion due to heat, the air rises, creating a draft that forces
it into the egg chamber. There it is caused to spread by muslin or
felt diaphragms so that no perceptible current of air strikes the
eggs. This type is the most popular type of small incubator on the
market. Its advantage will be more readily seen after the discussion
of the principles of incubation.
Hazy tales of Egyptian incubators have gone the rounds of poultry
papers these many years. More recently some accurate accounts from
American travelers and European investigators have come to light,
and as a result, the average poultry editor is kept busy trying to
explain how such wonderful results can be obtained "in opposition to
the well-known laws of incubation."
The facts about Egyptian incubators are as follows: They have a
capacity of 50 to 100 thousand eggs, and are built as a single large
room, partly underground and made of clay reinforced with straw. The
walls are two or three feet thick. Inside, the main rooms are little
clay domes with two floors.
The hatching season begins the middle of January and lasts three
months. A couple of weeks before the hatching begins, the fireproof
house is filled with straw which is set afire, thoroughly warming
the hatchery. The ashes are then taken out and little fires built in
pots are set around the outside of the big room. The little clay
rooms with the double floors are now filled with eggs. That is, one
is filled at a time, the idea being to have fresh eggs entering and
chicks moving out in a regular order, so as not to cause radical
changes in the temperature of the hatchery.
No thermometer is used, but the operator has a very highly
cultivated sense of temperature, such as is possessed by a cheese
maker or dynamite dryer. About the twelfth day the eggs are moved to
the upper part of the little interior rooms where they are further
removed from the heated floor. The eggs are turned and tested out
much as in this country. They are never cooled and the room is full
of the fumes and smoke of burning straw. The ventilation provided is
incidental.
This is about the whole story save for results. The incubator men
pay back three chicks for four eggs, and take their profits by
selling the extra chicks that are hatched above the 75 per cent.
This statement is in itself so astonishing and yet convincing, that
to add that the hatch runs between 85 per cent. and 90 per cent. of
all eggs set, and that the incubators of the Nile Delta hatch about
75,000,000 chicks a year seems almost superfluous. As for the
explanation of the results of the Egyptian incubators compared with
the American kerosene lamp type, I think it can best be brought
about by a consideration in detail of the scientific principles of
incubators.
Principles of Incubation.
HEAT.--To keep animal life, once started, alive and growing, we
need: First, a suitable surrounding temperature. Second, a fairly
constant proportion of water in the body substance. Third, oxygen.
Fourth, food.
Now, a fertile egg is a living young animal and as such its wants
should be considered. We may at once dispose of the food problem of
the unhatched chick, by saying that the food is the contents of the
egg at the time of laying, and as far as incubation is concerned, is
beyond our control.
In consideration of external temperature in its relation to life, we
should note: (A) the optimum temperature; (B) the range of
temperature consistent with general good health; (C) the range at
which death occurs. Just to show the principle at stake, and without
looking up authorities, I will state these temperatures for a number
of animals. Of course you can dispute the accuracy of these figures,
but they will serve to illustrate our purpose:
External External External Internal Internal
Optimum Healthful Fatal Optimum Fatal
Point Range Range Point Range
Man 70 0 to 100 50 to 140 98 90 to 106
Dog 60 70 to 140 70 to 140 101 95 to 110
Monkey 90 30 to 140 30 to 140 101 95 to 108
Horse 80 20 to 120 20 to 120 99 95 to 105
Fowl 80 20 to 140 20 to 140 107 100 to 115
Newly hatched
chick 90 70 to 100 40 to 120 108 100 to 115
Fertile egg
at start of
incubation 103 32 to 110 31 to 125 103 31 to 125
Egg incubated
three days 103 98 to 105 80 to 118 103 95 to 118
Egg incubated
eighteen days 103 75 to 105 50 to 118 106 98 to 116
This table shows, among other things, that we are considering in the
chick not a new proposition to which the laws of general animal life
do not apply, but merely a young animal during the process of growth
to a point where its internal mechanism for heat control, has power
to maintain the body temperature through a greater range of external
temperature change.
In the cooling process that occurs after laying the living cells of
the egg become dormant, and like a hibernating animal, the actual
internal temperature can be subjected to a much greater range than
when the animal is active. After incubation begins and cell activity
returns, and especially after blood forms and circulation commences,
the temperature of the chick becomes subject to about the same
internal range as with other warm blooded animals.
In the case of fully formed animals, the internal temperature is
regulated by a double process. If the external temperature be
lowered, more food substance is combined with oxygen to keep up the
warmth of the body, while, if the external temperature be raised,
the body temperature is kept low by the cooling effects of
evaporation. This occurs in mammals chiefly by sweating. Birds do
not sweat, but the same effect is brought about by increased
breathing. Now, the chick gradually develops the heat producing
function during incubation, until towards the close of the period it
can take care of itself fairly well in case of lowered external
temperature. The power to cool the body by breathing is not,
however, granted to the unhatched chick, and for this reason the
incubating egg cannot stand excess of heat as well as lack of it.
The practical points to be remembered from the above are:
First: Before incubation begins, eggs may be subjected to any
temperature that will not physically or chemically injure the
substance.
Second: During the first few days of the hatch, eggs have no
appreciable power of heat formation and the external temperature for
any considerable period of time can safely vary only within the
range of temperature at which the physiological process may be
carried on.
Third: As the chick develops it needs less careful guarding against
cooling, and must still be guarded against over-heating.
Fourth: It should be remembered, however, that eggs are very poor
conductors of heat, and if the temperature change is not great
several hours of exposure are required to bring the egg to the new
temperature.
Temperature is the most readily observed feature about natural
incubation and its control was consequently the first and chief
effort of the early incubator inventors.
A great deal of experimental work has been done to determine the
degree of temperature for eggs during incubation. The temperature of
the hen's blood is about 105 to 107 degrees F. The eggs are not
warmed quite to this temperature, the amount by which they fail to
reach the temperature of the hen's body depending, of course, upon
the surrounding temperature. 103 degrees F. is the temperature that
has been generally agreed upon by incubator manufacturers. Some of
these advise running 102 degrees the first week, 103 degrees the
second, 104 degrees the third. As a matter of fact it is very
difficult to determine the actual temperature of the egg in the box
incubator. This is because the source of heat is above the eggs and
the air temperature changes rapidly as the thermometer is raised or
lowered through the egg chamber. The advice to place the bulb of the
thermometer against the live egg is very good, but in practice quite
variable results will be found on different eggs and different parts
of the machine.
With incubators of the same make, and in all appearances identical,
quite marked variation in hatching capacity has been observed in
individual machines. Careful experimentation will usually show this
to be a matter of the way the thermometer is hung in relation to the
heating surfaces and to the eggs. Ovi-thermometers, which consists
of a thermometer enclosed in the celluloid imitation of an egg, are
now in the market and are perhaps as safe as anything that can be
used.
As was indicated in the previous section greater care in temperature
of the egg is necessary in the first half of the hatch. The
temperature of 102 degrees F. as above given is, in the writer's
opinion, too low for this portion of the hatch. An actual
temperature of 104 degrees at the top of the eggs will, as has been
shown by careful experimental work, give better hatches than the
lower temperature.
Moisture and Evaporation.
The subject of the water content of the egg and its relation to
life, is the least understood of poultry problems.
The whole study of the water content of the egg during incubation
hangs on the amount of evaporation. Now, the rates of evaporation
from any moist object is determined by two factors: vapor pressure
and the rate of movement of the air past the object. As incubation
is always carried on at the same temperature, the evaporating power
of the air is directly proportioned to the difference in the vapor
pressure of water at that temperature, and the vapor pressure of the
air as it enters the machine. Thus, in order to know the evaporative
power of the air, we have only to determine the vapor pressure of
the air and to remember that the rate of evaporation is in
proportion to this pressure, i.e.: when the vapor pressure is high
the evaporation will be slow and the eggs remain too wet, and when
the vapor pressure is low the eggs will be excessively dried out.
The reader is probably more familiar with the term relative humidity
than the term vapor pressure, but as the actual significance of
relative humidity is changed at every change in outside temperature,
the use of this term for expressing the evaporating power of the air
has led to no end of confusion.
The influence of air currents on evaporation is to increase it
directly proportional with the rate of air movement. Thus, 10 cubic
feet of air per hour passing through an egg chamber would remove
twice as much moisture as would 5 cubic feet.
If the percentage of water in any living body be changed a
relatively small amount, serious disturbances of the physiological
processes and ultimately death will result. The mature animal can,
by drinking, take considerable excess of water without danger, for
the surplus will be speedily removed by perspiration and by the
secretion from the kidneys. But the percentage of water in the
actual tissues of the body can vary only within a narrow range of
not more than three or four per cent. The chick in the shell is not
provided with means of increasing its water content by drinking or
diminishing it by excretion, but the fresh egg is provided with more
moisture than the hatched chick will require, and the surplus is
gradually lost by evaporation. This places the water content of the
chick's body at the mercies of the evaporating power of the air that
surrounds the egg during incubation.
To assume that these risks of uncertain rates of evaporation is
desirable, is as absurd as to assume that the risks of rainfall are
desirable for plant life. As the plants of a certain climate have
become adapted to the amount of soil moisture which the climate is
likely to provide, so the egg has by natural selection been formed
with about as much excess of water as will be lost in an average
season under the natural conditions of incubation. Plant life
suffers in drought or flood, and likewise bird life suffers in
seasons of abnormal evaporative conditions. This view is
substantiated by the fact that the eggs of water fowl which are in
nature incubated in damper places, have a lower water content than
the eggs of land birds.
The per cent. of water contained in the contents of fresh eggs is
about 74 per cent., or about 65.5 per cent, based on the weight,
shell included. Unfortunately no investigations have been made
concerning the per cent. of water present in the newly hatched
chick.
Upon the subject of the loss of water for the whole period of
incubation, valuable data has been collected at the Utah, Oregon and
Ontario Experiment Stations.
In these tests we find that as a rule the evaporation of eggs under
hens is less than in incubators. With both hens and incubators, the
rate of evaporation is greatest at the Utah Station, which one would
naturally expect from the climate. The eggs under hens at the
Ontario Station averaged about 12 per cent. loss in weight, and
those at the Utah Station about 15 per cent. At both stations,
incubators without moisture ran several per cent. higher evaporation
than eggs under hens. The conclusions at all stations were that the
addition of moisture to incubators was a material aid to good
hatches of livable chicks.
At Ontario the average evaporation ran from as low as 7 per cent. At
Utah it reached as high as 24 per cent. Now as the entire loss of
weight is loss of water, the solid contents remaining the same, and
as the original per cent, of water contained in the egg (shell
included) is only 65.5, the chicks of the two lots with the same
amount of solid substance would contain water in the proportion of
58.5 to 41.5. Based on the weight of the chick, this would make a
difference of water content of over 25 per cent.
That human beings or other animals could not exist with such
differences in the chemical composition of the body, is at once
apparent. In fact I do not believe that the chick can live under
such remarkable circumstances. As I have picked the extreme cases in
the series given, it is possible that these extremes were
experimental errors, and as in the Utah data, no information is
given as what happened to the chicks, I have no proof that they did
live. But from the large number of hatches that were recorded below
9 per cent, and above 15 per cent., giving a variation of the actual
water content in the chick's body of about 10 per cent., it is
evident that chicks do hatch under remarkable physiological
difficulties. One explanation that suggests itself is, that as there
is considerable variation in evaporation of individual eggs due to
the amount of shell porosity, and the chicks that hatch in either
case may be the ones whose individual variations threw them nearer
the normal.
By a further study from the Ontario data of the relation of the
evaporation to the results in livable chicks, it can be readily
observed that all good hatches have evaporation centering around the
12 per cent. moisture loss, and that all lots with evaporations
above 15 per cent. hatch out extremely poor.
The general averages of the machines supplied with some form of
moisture was 35 per cent. of all eggs set, in chicks alive at four
weeks of age, while the machines ran dry gave only 20 per cent. of
live chicks at a similar period.
Now, I wish to call attention to a further point in connection with
evaporation. If the final measure of the loss of weight by
evaporation were the only criterion of correct conditions of
moisture in the chick's body, the hatches that show 12 per cent., or
whatever the correct amount of evaporation may be, should be
decidedly superior to those on either side. That they are better,
has already been shown. But they are far from what they should be.
An explanation is not hard to find. The correct content of moisture
is not the only essential to the chick's well being at the moments
of hatching, but during the whole period of incubation. Under our
present system of incubation, the chick is immediately subject to
the changing evaporation of American weather conditions. The data
for that fact, picked at random, will be of interest. The following
table gives the vapor pressure at Buffalo, N. Y., for twenty
consecutive days in April:
April 1..................170
2..................130
3...................95
4..................103
5..................110
6..................106
7..................154
8..................183
9..................245
10.................311
11.................342
12.................286
13.................219
14.................248
15.................217
16.................193
17.................241
18.................306
19.................261
20.................204
Supposing a hatch to be started at the beginning of the above
period, by the end of the first week, with the excessive
evaporation, due to a low vapor pressure, the eggs would all be
several per cent. below the normal water content; the fact that the
next week was warm and rainy, and the vapor pressure rose until the
loss was entirely counterbalanced, would not repair the injury, even
though the eggs showed at the end of incubation exactly the correct
amount of shrinkage. A man might thirst in the desert for a week,
then, coming to a hole of water fall in and drown, but we would
hardly accept the report of a normal water content found at the
post-mortem examination as evidence that his death was not connected
with the moisture problem.
The change of evaporation, due to weather conditions, is, under
hens, less marked than in incubators. This is because there are no
drafts under the hen, and because the hen's moist body and the moist
earth, if she sets on the ground, are separate sources of moisture
which the changing humidity of the atmosphere does not affect. Among
about forty hens set at different times at the Utah Station and the
loss of moisture of which was determined at three equal periods of
six days each, the greatest irregularity I found was as follows: 1st
period, 5.81 per cent; 2d period, 3.86 per cent; 3d period, 6.15 per
cent. Compare this with a similar incubator record at the same
station in which the loss for the three periods was 5.63, 9.18 and
2.15.
I think the reader is now in position to appreciate the almost
unsurmountable difficulties in the proper control of evaporation
with the common small incubator in our climate. It is little wonder
that one of our best incubator manufacturers, after studying the
proposition for some time, threw over the whole moisture
proposition, and put out a machine in which drafts of air were
slowed down by felt diaphragms and the use of moisture was strictly
forbidden.
The moisture problem to the small incubator operator presents itself
as follows: If left to the mercies of chance and the weather, the
too great or too little evaporation from his eggs will yield hatches
that will prove unprofitable. In order to regulate this evaporation,
he must know and be able to control both vapor pressure and the
currents of air that strike the eggs. Now he does not know the
amount of vapor pressure and has no way of finding it out. The
so-called humidity gauges on the market are practically worthless,
and even were the readings on relative humidity accurately
determined, they would be wholly confusing, for their effect of the
same relative humidity on the evaporation will vary widely with
variations of the out-of-door temperature.
If the operator knows or guesses that the humidity is too low, he
can increase it by adding water to the room, or the egg chamber, but
he cannot tell when he has too much, nor can he reduce the vapor
pressure of the air on rainy days when nature gives him too much
water. As to air currents he is little better off--he has no way to
tell accurately as to the behavior of air in the egg chamber and
changes in temperature of the heater or if the outside air will
throw these currents all off, since they depend upon the draft
principle.
Taking it all in all, the man with the small incubator had better
follow the manufacturer's directions and trust to luck.
The writer has long been of the conviction that a plan which would
keep the rate of evaporation within as narrow bounds as we now keep
the temperature, would not only solve the problem of artificial
incubation, but improve on nature and increase not only the numbers
but the vitality or livability of the chicks. With a view of
studying further the relations between the conditions of atmospheric
vapor pressure, and the success of artificial incubation, I have
investigated climatic reports and hatching records in the various
sections of the world.
The following are averages of the monthly vapor pressures at four
points in which we are interested:
Buffalo, St. Louis, San Fran- Cairo
Month N.Y. Mo. cisco. Egypt
January 87 98 311 279
February 81 94 310 288
March 138 224 337 287
April 171 283 332 311
May 301 423 317 328
June 466 550 345 365
July 546 599 374 413
August 496 627 382 435
September 429 506 389 372
October 285 327 342 365
November 271 225 285 321
December 143 133 243 397
A study of the extent of daily variations is also of interest. As a
general thing they are less extreme in localities when the seasonal
variations are also less. In Cairo, however, which has a seasonal
variation greater than San Francisco, the daily variations during
the hatching season are much less than in California. This is due to
a constant wind from sea to land, and an absolute absence of
rainfall, conditions for which Egypt is noted.
Nearness to a coast does not mean uniform vapor pressure, for with
wind alternating from sea to land, it means just the opposite.
As will be readily seen the months in spring which give the best
hatches, occupy a medium place in the humidity scale. The fact that
both hens and machines succeed best in this period, is to me very
suggestive of the possibility that with an incubator absolutely
controlling evaporation, much of the seasonal variation in the
hatchability would disappear.
The uniform humidity of the California coast is shown in the above
table. This is not inconsistent with the excellent results obtained
at Petaluma.
The Egyptian hatcher in his long experience has learned just about
how much airholes and smudge fire are necessary to get results. With
these kept constant and the atmosphere constant, we have more nearly
perfect conditions of incubation than are to be found anywhere else
in the world, and I do not except the natural methods. The climatic
conditions of Egypt cannot be equaled in any other climate, but as
will be shown in the last section of this chapter, their effect can
be duplicated readily enough by modern science and engineering.
Mr. Edward Brown, who was sent over here by the English Government
to investigate our poultry industry, was greatly surprised at our
poor results in artificial incubation. Compared with our
acknowledged records of less than 50 per cent. hatches, he quotes
the results obtained in hatching 18,000 eggs at an English
experiment station as 62 per cent. I have not obtained any data of
English humidity, but it is undoubtedly more uniform than the
eastern United States.
Ventilation--Carbon Dioxide.
The last of the four life requisites we have to consider is that of
oxygen. The chick in the shell, like a fish, breathes oxygen which
is dissolved in a liquid. A special breathing organ is developed for
the chick during its embryonic stages and floats in the white and
absorbs the oxygen and gives off carbon dioxide. The amount of this
breathing that occurs in the chick is at first insignificant, but
increases with development. At no time, however, is it anywhere
equal to that of the hatched chicks, for the physiological function
to be maintained by the unhatched chicks requires little energy and
little oxidation.
Upon the subject of ventilation in general, a great misunderstanding
exists. Be it far from me to say anything that will cause either my
readers or his chickens to sleep less in the fresh air, yet for the
love of truth and for the simplification of the problem of
incubation, the real facts about ventilation must be given.
In breathing, oxygen is absorbed and carbon dioxide and water vapor
are given off. It is popularly held that abundance of fresh air is
necessary to supply the oxygen for breathing and that carbon dioxide
is a poison. Both are mistakes. The amount of oxygen normally in the
air is about 20 per cent. Of carbon dioxide there is normally three
hundredths of one per cent. During breathing these gasses are
exchanged in about equal volume. A doubling or tripling of carbon
dioxide was formerly thought to be "very dangerous." Now, if the
carbon dioxide were increased 100 times, we would have only three
per cent., and have seventeen per cent. of oxygen remaining. This
oxygen would still be of sufficient pressure to readily pass into
the blood. We might breathe a little faster to make up for the
lessened oxygen pressure. In fact such a condition of the air would
not be unlike the effects of higher altitudes.
Some investigations recently conducted at the U.S. Experiment
Station for human nutrition, have shown the utter misconception of
the old idea of ventilation. The respiratory calorimeter is an
air-tight compartment in which men are confined for a week or more
at a time while studies are being made concerning heat and energy
yielded by food products. It being inconvenient to analyze such an
immense volume of air as would be necessary to keep the room
freshened according to conventional ventilation standards,
experiments were made to see how vitiated the air could be made
without causing ill effects to the subject.
This led to a remarkable series of experiments in which it was
repeatedly demonstrated that a man could live and work for a week at
a time without experiencing any ill effects whatever in an
atmosphere of his own breath containing as high as 1.86 per cent. of
carbon dioxide, or, in other words, the air had its impurity
increased 62 times. This agrees with what every chemist and
physiologist has long known, and that is that carbon dioxide is not
poisonous, but is a harmless dilutant just as nitrogen. This does
not mean that a man or animal may not die of suffocation, but that
these are smothered, as they are drowned, by a real absence of
oxygen, not poisoned by a fraction of 1 per cent. of carbon dioxide.
In the same series of experiments, search was made for the
mysterious poisons of the breath which many who had learned of the
actual harmlessness of carbon dioxide alleged to be the cause of the
ill effects attributed to foul air. Without discussion, I will say
that the investigators failed to find such poisons, but concluded
that the sense of suffocation in an unventilated room is due not to
carbon dioxide or other "poisonous" respiratory products, but is
wholly due to warmth, water vapor, and the unpleasant odors given
off by the body.
The subject of ventilation has always been a bone of contention in
incubator discussions. With its little understood real importance,
as shown in the previous section, and the greatly exaggerated
popular notions of the importance of oxygen and imagined poisonous
qualities of carbon dioxide, the confusion in the subject should
cause little wonder.
A few years ago some one with an investigating mind decided to see
if incubators were properly ventilated, and proceeded to make carbon
dioxide determinations of the air under a hen and in an incubator.
The air under the hen was found to contain the most of the obnoxious
gas. Now, this information was disconcerting, for the hen had always
been considered the source of all incubator wisdom. Clearly the
perfection of the hen or the conception of pure air must be
sacrificed. Chemistry here came to the rescue, and said that carbon
dioxide mixed with water, formed an acid and acid would dissolve the
lime of an egg shell. Evidently the hen was sacrificing her own
health by breathing impure air in order to soften up the shells a
little so the chicks could get out. Since it could have been
demonstrated in a few hours in any laboratory, that carbon dioxide
in the quantities involved, has no perceptible effect upon egg
shells, it is with some apology that I mention that quite a deal of
good brains has been spent upon the subject by two experiment
stations. The data accumulated, of course, fails to prove the
theory, but it is interesting as further evidence of the
needlessness in the old fear of insufficient ventilation.
At the Ontario Station, the average amounts of carbon dioxide under
a large number of hens was .32 of one per cent., or about ten times
that of fresh air, or one-sixth of that which the man breathed so
happily in the respiratory calorimeter. With incubators, every
conceivable scheme was tried to change the amount of carbon dioxide.
In some, sour milk was placed which, in fermenting, gives off the
gas in question. Others were supplied with buttermilk, presumably to
familiarize the chickens with this article so they would recognize
it in the fattening rations. In other machines, lamp fumes were run
in, and to still others, pure carbon dioxide was supplied. The
percentage of the gas present varied in the machines from .06 to .58
of one per cent. The results, of course, vary as any run of hatches
would. The detailed discussion of the hatches and their relation to
the amount of carbon dioxide as given in Bulletin 160 of the Ontario
Station, would be unfortunately confusing to the novice, but would
make amusing reading for the old poultryman. Speaking of a
comparison of two hatches, the writer, on page 53 of the bulletin
says, "The increase in vitality of chicks from the combination of
the carbon dioxide and moisture over moisture only, amounting, as it
does, to 4.5 per cent. of the eggs set, seems directly due to the
higher carbon dioxide content." I cannot refrain from suggesting
that if my reader has two incubators, he might set up a Chinese
prayer machine in front of one and see if he cannot in like manner
demonstrate the efficacy of Heavenly supplications in the hatching
of chickens.
The practical bearing of the subject of ventilation in the small
incubator is almost wholly one of evaporation. The majority of such
machines are probably too much ventilated. In a large and properly
constructed hatchery, such as is discussed in the last section of
this chapter, the entire composition of the air, as well as its
movement, is entirely under control. Nothing has yet been brought to
light that indicates any particular attention need be given to the
composition of such air save in regard to its moisture content, but
as the control of this factor renders it necessary that the air be
in a closed circuit, and not open to all out-doors, it will be very
easy to subject the air to further changes such as the increasing
oxygen, if such can be demonstrated to be desirable.
Turning Eggs.
The subject of turning eggs is another source of rather meaningless
controversy. Of course, the hen moves her eggs around and in doing
so turns them. Doubtless the reader, were he setting on a pile of
door knobs as big as his head, would do the same thing. As proof
that eggs need turning, we are referred to the fact that yolks stick
to the shell if the eggs are not turned. I have candled thousands of
eggs and have yet to see a yolk stuck to the shell unless the egg
contained foreign organism or was several months old. However, I
have seen hundreds of blood rings stuck to the shell. Whether the
chick died because the blood rings stuck or whether the blood rings
stuck because the chicken died I know not, but I have a strong
presumption that the latter explanation is correct, for I see no
reason if the live blood ring was in the habit of sticking to the
shell, why this would not occur in a few hours as well as in a few
days.
In the year 1901 I saw plenty of chicks hatched out in Kansas in egg
cases, kitchen cupboards and other places where regular turning was
entirely overlooked.
Mr. J.P. Collins, head of the Produce Department of Swift & Co.,
says that he was one time cruelly deserted in a Pullman smoker for
telling the same story. The statement is true, however, in spite of
Mr. Collins' unpleasant experience. Texas egg dealers frequently
find hatched chickens in cases of eggs.
Upon the subject of turning eggs the writer will admit that he is
doing what poultry writers as a class do on a great many occasions,
i.e.: expressing an opinion rather than giving the proven facts. In
incubation practice it is highly desirable to change the position of
eggs so that unevenness in temperature and evaporation will be
balanced. When doing this it is easier to turn the eggs than not to
turn them, and for this reason the writer has never gone to the
trouble of thoroughly investigating the matter. But it has been
abundantly proven that any particular pains in egg turning is a
waste of time.
Cooling Eggs.
The belief in the necessity of cooling eggs undoubtedly arose from
the effort to follow closely and blindly in the footsteps of the
hen. With this idea in mind the fact that the hen cooled her eggs
occasionally led us to discover a theory which proved such cooling
to be necessary. A more reasonable theory is that the hen cools the
eggs from necessity, not from choice. In some species of birds the
male relieves the female while the latter goes foraging.
But there is no need to argue the question. Eggs will hatch if
cooled according to custom, but that they will hatch as well or
better without the cooling is abundantly proven by the results in
Egyptian incubators where no cooling whatever is practiced.
Searching for the "Open Sesame" of Incubation.
The experiment station workers have, the last few years, gone a
hunting for the weak spot in artificial incubation. Some reference
to this work has already been made in the sections on moisture and
ventilation. Before leaving the subject I want to refer to two more
efforts to find this key to the mystery of incubation and in the one
case at least correct an erroneous impression that has been given
out.
At the Ontario Station a patent disinfectant wash called "Zenoleum"
was incidentally used to deodorize incubators. Now, for some reason,
perhaps due to the belief that white diarrhoea was caused by a germ
in the egg, this idea of washing with Zenoleum was conceived to be a
possible solution of the incubator problem. In the numerous
experiments at that station in 1907 Zenoleum applied to the machine
in various ways was combined with various other incipient panaceas
and at the end of the season the results of the various combinations
were duly tabulated. The machine with buttermilk and Zenoleum headed
the list for livable chicks.
For reasons explained in the chapter on "Experiment Station Work,"
the idea of contrasting the results of one hatch with one sort with
the average results of many hatches of another sort is very poor
science. Feeling that the Station men would hardly be guilty of
expressing as they did in favor of such a method without better
reason, I very carefully went over the results and compared all
machines using Zenoleum with all machines without it. The results in
favor of Zenoleum were less marked but still perceptible. I was
somewhat puzzled, as I could see no rational explanation of the
relation between disinfecting incubator walls and the hatchability
of the chick in its germ-proof cage. Finally I hit upon the scheme
of arranging the hatches by dates and the explanation became at once
apparent. The hatching experiments had extended from March to July,
but the Zenoleum hatches were grouped in April and early in May,
when, as one would expect from weather conditions, all hatches were
running good. After allowing for this error Zenoleum appeared as
harmless and meaningless as would the Attar of Roses.
The second link after the missing link of incubation to which I wish
to call your attention also occurred at the Ontario Station. The
latter case, however, is happier in that no unwarranted conclusions
were drawn and that an interesting bit of scientific knowledge was
added to the world's store. The conception to be tested was an
offshoot from the carbon dioxide theory. You will remember at the
Utah Station the idea was that carbon dioxide was to dissolve the
shell so the chick could break out easier.
At the Guelph Station the conception was that the carbon dioxide
might dissolve the lime of the shell for the chick to use in "makin'
hisself." As an egg could not be analyzed fresh and then hatched, a
number were analyzed from the same hens and others from those hens
were then incubated with the various amounts of carbon dioxide,
buttermilk, Zenoleum, and other factors. The lime content of the
contents of the fresh egg averaged about .04 grams. At hatching time
the lime in the chick's body averaged about .20 grams and was always
several times as great as the maximum of the eggs.
Clearly calcium phosphate of the chick's bones is made by the
digestion of the calcium carbonate from the shell and its
combination with the phosphorus of the yolk. Certainly a remarkable
and hitherto unexplained fact. The amount of lime required is not
great enough, however, to materially weaken the shell, but, of
course, the process is vital to the chick as bones are quite
essential to his welfare, but it is an "inside affair" of which the
three-tenths of one per cent of carbon dioxide incidentally present
under the hen is entirely irrelevant.
A further observation made by the investigator is that the chicks
which obtained the lowest amount of lime were abnormally weak. As
long as we are powerless to aid the chick in digesting lime this
fact, like the other, belongs in the field of pure, rather than
applied science. I think that we are safe in saying that the
weakness caused the shortage of lime rather than vice versa; if the
writer remembers runts in other animals are usually a little short
of bone material.
The chemist of the station is to be given special credit for not
jumping at conclusions. In the summary of this work he states:
"There is apparently no connection between the amount of lime
absorbed by the chick and the amount of carbon dioxide present
during incubation."
The Box Type of Incubator In Actual Use.
Although the fact is not so advertised and frequently not recognized
even by the makers, the success of existing incubators is directly
proportional to the extent with which they control evaporation. In
order to show this I have only to call attention briefly to two or
three of the most successful types of incubators on the market.
Let me first repeat that evaporation increases with increased air
currents and with decreased vapor pressure. Now, the vapor pressure
undergoes all manner of changes with the passing of storm centers
and the changes of prevailing winds. But there is a general tendency
for vapor pressure to increase with increase in outside temperature.
Now, the movement of air in all common incubators depends upon the
draft principle and the greater the difference in machine
temperature and outside temperature the greater will be this draft.
Thus, we have two factors combining to cause variation in the rate
of evaporation. The tendency for the rate of airflow to vary is
diminished when a cellar is used for an incubator room, but the
cellar does not materially remedy the climatic variation in vapor
pressure.
The general tendency of incubators as ordinarily constructed, is to
dry out the eggs too rapidly. With a view of counteracting this,
water is placed in pans in the egg room. A surface of water exposed
to quiet air does not evaporate as fast as one might think, as is
easily shown by the fact that air above rivers, lakes and even seas
is frequently far from the saturation point. The result of the
moisture pan with a given current of air is that the vapor pressure
is increased a definite amount, but by no means is it regulated or
made uniform. Inasmuch as too much shrinking is the most prevalent
fault in box incubators, the use of moisture is on the whole
beneficial, but in hot, murky weather, with less circulation and
higher outside vapor pressure, the moisture is overdone and the
operator condemns the system.
The subject not being clearly understood and no means being
available for vapor pressure determinations, the system results in
confusion and disputes. When the felt diaphragm machine was brought
into the market it was advertised as a no-moisture machine. The
result of the diaphragm is that of choking off air movement and
consequently reducing evaporation. This gives exactly the same
results as the use of moisture, but the machine is easier to operate
and seemed to do away with the vexatious moisture problem which,
together perhaps, with some fancied resemblance of felt diaphragms
to hen feathers, has resulted in the widespread use of this type of
machine.
The latest effort along the lines of reducing evaporation is the
sand tray machine that followed in the wake of the Ontario
investigation. This device simply gives a greater evaporating
surface to the water and hence a greater addition to the vapor
pressure. The results in practice I had given me by a man who last
year hatched sixty-five thousand chicks and as many more ducklings.
He said: "The sand tray early in the season gave the best hatches
and most vigorous chicks we had, but later on things got too wet and
the chickens drowned." No nicer demonstration of science in practice
could be desired.
In the present-day incubator of either type we are wholly at the
mercy of sudden climatic changes of vapor pressure. For the slower
changes from season to season some control by greater and less
amounts of supplied moisture, or by ventilator slides is available,
but little understood and seldom practiced.
It will certainly be of interest to my readers to know the actual
hatches obtained with the prevailing type of box incubator. By
actual hatches we mean the per cent. of live chicks taken out of the
machine to the per cent. of eggs put in. The ordinary published
hatches, based on one per cent. of fertile hatches, are a delusion
and a snare. When eggs are tested out many dead germs come out with
them and the separation of microscopic dead germs from the infertile
egg is, of course, impossible. Such padded and show hatching records
do not interest us.
Where incubators are run on top of the ground I have found the
results to be poor and to improve, the bigger and deeper and damper
and warmer and less ventilated the cellar is made. The reason for
this is plain. In such a cellar the vapor pressure of the air is not
only greater but is less influenced by the shifting vapor pressure
of the outside air. In a good cellar the operator, though his
knowledge of the factors with which he deals is grievously
deficient, learns, through long and costly experience, about what
addition of moisture or about what rate of ventilation will give him
the best results. In the room more subject to outside influences,
the conditions are so constantly changing that uniformity of
practice never gives uniform results, and hence the operator is
without guidance, either intelligent or blind, and the results are
wholly a product of chance.
As proof of my contention I may give results of a series of full
season hatches for 1908, each involving several thousand eggs.
First, a state experiment station, the name of which I do not care
to publish. Incubators kept in a cement basement which has flues in
which fires were built to secure "ample ventilation." This caused a
strong draft of cold, dry air, making the worst possible condition
for incubation. The hatch for the season averaged 25 per cent. and
was explained by lack of vitality in the stock.
Second, Ontario Agricultural College. A room above ground, moisture
used in most machines and various other efforts being made to
improve the hatches by a staff of half a dozen scientists. Results:
Hatch 48 per cent.--incubator manufacturers call the experimenters
names and say they are ignorant and prejudiced.
Third, Cornell University: dry ventilated basement representing
typical conditions of common incubator practice of the country.
Results: Hatch 52 per cent., results when given out commonly based
on fertile eggs and every one generally pleased.
Fourth: One of the most successful poultrymen in New York State, who
has, without knowing why, hit upon the plan of using a no-moisture
type of incubator in a basement which is heated with steam pipes,
which maintains temperature at 70 degrees and has a cement floor
which is kept covered with water. Results: Hatch 59 per cent.
Fifth: As a fifth in such a series I might mention again the
Egyptian machine with the uniform vapor pressure of the climate and
the three chicks exchanged for four eggs.
While an official in the United States Department of Agriculture, I
gathered data from original records of private plants covering the
incubation of several hundred thousand eggs. Such information was
furnished me in confidence as a public official and as a private
citizen I have no right to publish that which would mean financial
profit or loss to those concerned.
Of records where there were ten thousand or more eggs involved, the
lowest I found was 44 per cent. and the highest, that mentioned as
the fourth case above, or 59 per cent. The great majority of these
records hung very closely around the 50 per cent. mark.
The following is a fair sample of such data. It is the record
of hatching hen eggs for the first six months of 1908, at one
of the largest poultry plants in America:
Eggs Chicks Per Cent.
Month Set Hatched Hatched
January 4,213 1,585 37 2-3
February 6,275 2,339 33 3-4
March 17,990 6,993 38 1-3
April 18,819 10,265 54 1-2
May 24,458 14,438 59
June 13,100 6,614 55
------ ------ ------
Total 84,855 42,234 50 p.c.
The Future Method of Incubation.
The idea of the mammoth incubator which would hatch eggs by the
hundred thousand and a minimum of expense is the dream of the
American incubator inventor. We have long had available such methods
of insulation and regulating the supply of heat as would point to
the practicability of such a dream.
The past efforts in this direction have fallen down for the
following simple reason: All eggs were placed in a single big room
with a view of the man's entering the room to take care of them.
Contact with cold walls, the opening of doors, the hatching of
chicks or introduction of fresh eggs set up air currents, the hot
air rising and the cold air settling until great differences in
temperature would be found in the room. No systematic regulation of
evaporation was contemplated, as the principles at stake or the
means of such regulation were unknown.
The attempt just referred to was made several years ago by one of
the most successful of incubator manufacturers and because of his
failure other inventors were inclined to steer clear of the
proposition. Meanwhile the need of such an incubator has grown
enormously. At the time that above effort was made no duck ranch
existed whose annual production ran over thirty or forty thousand
ducklings, whereas we now have several in the one hundred thousand
class.
Much more remarkable has been the growth of the day-old chick
business. The discovery that newly hatched chicks could be
successfully shipped hundreds of miles with less loss than shipping
eggs for hatching, has resulted in a few years' time in the growth
of hatcheries of considerable size where chicks are hatched by means
of common incubators. Still another opportunity for the use of large
hatcheries has been by the growth of poultry communities. There are
other communities besides those mentioned in this book which would
amply support public hatcheries. If half the poultry growers of
Lancaster County, Pa., were to be prevailed upon to patronize a
public hatchery, the county would support between fifteen and twenty
100,000 egg incubators. Any of the numerous trolley centers in
Indiana, Ohio and Southern Michigan would likewise be profitable
locations for the establishment of public hatcheries.
The demand for the incubator of large capacity has, within the last
year or so, brought two or three "mammoth" incubators into the
market. The devices I now refer to consist of a row of box
incubators which, instead of being heated by single lamps, are
heated by continuous hot water pipes. This scheme effects a
considerable saving in fuel cost and labor, but the bulkiness of
construction and the woeful lack of evaporation control are still to
be dealt with.
The writer now wishes briefly to describe the plan of construction
and operation of a new type of hatchery, the success of which has
recently been made feasible by inventions and technical knowledge
hitherto unavailable. The plan of the hatchery is on that of a cold
storage plant as far as insulation and general construction go. The
eggs are kept in bulk in special cases which are turned as a whole
and may rest on either of four sides. At hatching time the eggs are
spread out in trays in a special hatching room, which is only large
enough to accommodate chicks to the amount of one-sixth of the
incubator capacity, for twice a week deliverings, or one-third if
weekly deliveries are desired.
There are no pipes or other sources of heat in the egg chambers. All
temperature regulation is by means of air heated (or cooled as the
case may be) outside of the egg rooms and forced into the egg rooms
by a motor driven cone fan, maintaining a steady current of air, the
rate of movement of which may be varied at will. The air movement
maintained will always be sufficiently brisk, however, to prevent an
unevenness of temperature in different parts of the room.
So simple is this that the reader will doubtless wonder why it was
not developed earlier. The reason is that air subject to the
climatic influences will, with any forced draft sufficient to
equalize temperature, result in a fatal rate of evaporation.
Sprinkling the air has not generally been thought practical because
of the notion that air must not be used in the egg chamber but once,
which involved quite a waste of heat necessary in warming a large
bulk of air and evaporating sufficient water. Moreover, no means
has, in the past, been available for making a sufficiently accurate
measurement of the evaporating power of the air.
The hair hygrometers commonly sold to incubator operators are known
by scientists to be absolutely unreliable. The range between the wet
and dry bulb thermometers was found in the Ontario experiments to
give readings with and without fanning that varied 15 to 20 per
cent. in relative humidity which, at the temperature of an egg
chamber, would amount to a variation of three to four hundred of
vapor pressure units, which, with the forced draught plan, would
ruin a hatch of eggs in a few hours. The sling psychrometer as used
by the U.S. Weather Bureau should, in the hands of an expert, give
results making possible measurements accurate to two or three per
cent. of relative humidity or forty to sixty units of vapor
pressure. In contrast with these blundering instruments we now have
available an instrument with which the writer has frequently
determined vapor pressure accurately to within a range of two or
three vapor pressure units and the instrument is capable of being
constructed for even finer work.
As it is only by means of air with the moisture content absolutely
controlled that the use of a large room becomes possible, we can now
see why this type of hatching remained so long undeveloped. By means
of such vapor pressure control the large egg chamber is not only
feasible but the rate of evaporation at once becomes subject to the
control of the operator and we achieve a perfection in artificial
incubation hitherto unattained.
The means by which the air moisture is regulated is similar to that
used in up-to-date cold storage plants where the air is made moist
by sprinkling and dried with deliquescent salts. The regulation of
vapor pressure, like that of temperature, may be by electrically
moved dampers which switch a greater or less proportion of the
incoming current to the sprinkler or dryer as the case may be. The
ordinary incubator thermostat gives the necessary impulse for the
control of the temperature dampers, while the instrument above
referred to is used for the vapor pressure control.
As the entire air circuit is closed, the chemical composition of the
air may also be regulated at will. This results in a reduction of
the quantity of heat required to a minimum; in fact, with the
incubator in full swing, the air will, at times, need cooling rather
than warming.
The question of the cost of incubation by this method, or of profit
of such a hatchery operated for the public is almost wholly one of
the size of operations. Where sufficient eggs may be obtained and
sufficient demand exists for the chicks to make it profitable to
operate, the additional cost of hatching extra chicks will be
insignificant compared with the present system.
The Egyptian poultryman gives four eggs for three chicks, but the
American poultryman would be willing to give four eggs for one
chick, as is shown by the fact that he sells eggs for from 1 to 3
cents apiece and buys day-old chicks for ten to fifteen cents. A
plant with a seasonable capacity of 100,000 eggs has a basis to work
upon something as follows:
With a fifty per cent. hatch and chicks at 10 cents each there would
be a gross income of $5,000 annually. From this we must subtract for
eggs at 2 cents each, $2,000. Salary for operator $1,000, wages for
helper $300. Fuel, supplies and repairs $500. Cost of delivery and
sales of chicks $200. This leaves a residue of $1,000, which would
pay a 20 per cent. interest on the necessary investment of $5,000.
Personally, I think this is about the minimum unit of hatching that
would prove worth while as independent institutions.
Any increase in the percentage of the hatch would, of course, reduce
the unit of size necessary for profitable operation. Upon a single
poultry plant as a duck farm the cost of operation would be
materially reduced, as the operator himself would take the place of
the intelligent manager and the cost of gathering eggs and the
delivery of the product would be eliminated.
The most profitable method of hatchery operation undoubtedly will be
upon a plan analogous to what, in creamery operation, is called
centralization. The success of this scheme depends upon the fact
that transportation and agencies at country stores are relatively
less important items of expense than plant construction and high
salaries for skilled labor. A hatchery with a million capacity can
be built and run at not more than twice the cost of one
hundred-thousand plant and better men can be kept in charge of it. A
portion of the saving will of course be expended in maintaining a
system of buying eggs and selling chicks.
The material advantage of operating a hatchery in connection with a
high-class egg handling and poultry packing establishment, or as one
feature of a poultry community, is at once apparent, for the system
of collecting the market produce will be utilized for gathering eggs
and distributing chicks, each business helping the other.
The public hatchery also gives an excellent opportunity for the
introduction of good stock among farmers who would be too shiftless
to acquire it by ordinary methods.
CHAPTER VII
FEEDING
The old adage that a little knowledge is a dangerous thing is
nowhere better illustrated than in the scientific phases of poultry
feeding. The attempted application of the common theoretical feeding
standards to poultry has caused not only a great waste of time but
has also resulted in expenditures for high-priced feeds when cheaper
feeds would have given as good or better results.
The so-called science of food chemistry is really a rough
approximation of things about which the actual facts are unknown.
Such knowledge bears the same relation to accurate science as the
maps of America drawn by the early explorers do to a modern atlas.
Like these early efforts of geography the present science of food
chemistry is all right if we realize its incompleteness. In
practice, the poultryman, after a general glance at the "map," will
find a more reliable guide in simpler things.
I am writing this book for the poultryman, not the professor, and
because I state that the particular kind of science wherein the
professor has taken the most pains to teach the poultryman is
comparatively useless, I fear it may arouse a mistrust of the value
of science as a whole. I know of no way to prevent this except to
point out the distinction between scientific facts and guesses
couched in scientific language.
When a scientist states that a hen cannot lay egg shells containing
calcium without having calcium in her food, that is a fact, and it
works out in practice, for calcium is an element, and the hen cannot
create elementary substances. When the same scientist, finding that
an egg contains protein, says that wheat is a better egg food than
corn because it has the largest amount of protein, that is a guess
and does not work in practice because protein is not a definite
substance, but the name of a group of substances of which the
scientist does not know the composition, and which may or may not be
of equal use to the hen in the formation of eggs.
All substances of which the world is made are composed of elements
which cannot be changed. When these elements are combined they form
definite substances with definite proportions entirely independent
of the original elements. The pure diamond is carbon. Gasoline is
carbon and hydrogen. Several hundred other things are also carbon
and hydrogen. Sugar is carbon combined with hydrogen and oxygen.
These three elements make several thousand different substances,
including fats, alcohol and formaldehyde. Hydrocyanic acid is carbon
combined with hydrogen and nitrogen, and is the most deadly poison
known.
The failure of food science is partly because we do not know the
composition of many of the substances of food and partly because
these substances are changed in the animal body in a manner which we
do not understand and cannot control.
Conventional Food Chemistry
The conventional analysis of feeding stuff divides the food
substances in water, carbohydrates, fat, protein and ash. The amount
of water in the body is all-important, but, with the exception of
eggs during incubation, I confess I prefer to rely upon the
chicken's judgment as to the amount required.
The carbohydrate group contains starch, sugar, cellulose and a
number of other things. Carbohydrates constitute two-thirds to
three-fourths of all common rations and nine-tenths of that amount
is starch. The proposition of how much carbohydrates the hen eats is
chiefly determined by the quantity of grain she consumes.
Of fats there are many kinds of which the composition is definitely
known. The amount of fats the hen eats is unimportant because she
makes starch into fat. The protein or nitrogen containing substances
of the diet is the group of food substances over which most of the
theories are expounded. The hen can make egg fat from corn starch or
cabbage leaves because they contain the same elements. She cannot
make egg white from starch or fat because the element of nitrogen
which is in the egg white is lacking in the starch and fats.
The substances that have nitrogen in them are called protein. They
are very complex and difficult to analyze. In digestion these
proteins are all torn to pieces and built up into other kinds of
protein. Just as in tearing down an old house, only a portion of the
material can be used in a new house, so it is with protein and
laboratory analysis cannot tell us how much of the old house can be
utilized in building the new one.
In practice the whole subject simmers down to the proposition of
finding out by direct experiment whether the hen will do the work
best on this or that food, irregardless of its nitrogen content as
determined in the laboratory.
The results of many experiments and much experience has shown that
lean meat protein will make egg protein and chicken flesh protein
and that vegetable protein pound for pound is not its equal. I know
of no results that have proven that the high priced vegetable foods
such as linseed meal, gluten feed, etc., have proven a more valuable
chicken food than the cheapest grains.
With cows and pigeons this is not the case, but the hen is not a
vegetarian by nature and high priced vegetable protein doesn't seem
to be in her line. Of the three standard grains there is some
indication of the value of the proteids for chickens and of the
following ranks, 1st oats, 2d corn, 3d wheat.
The false conceptions of the value of wheat proteids has been
specially the cause of much waste of money. Digestive trials and
direct experiments both show that, as chicken foods, wheat is worth
less, pound for pound, than corn and yet, though much higher in
price, it is still used not only as a variety grain, but by many
poultrymen as the chief article of diet. Wheat contains only 3 per
cent. more proteid than corn. The man who substitutes wheat at one
and one-half cents a pound for corn worth one cent a pound pays 17
cents a pound for his added protein. In beef scrap he could get the
protein for 5 cents a pound and have a very superior article
besides.
Milk as a source of protein ranks between the vegetable proteids and
those of meat. It is preferably fed clabbered. The dried casein
recently put on the market is a valuable food but is not worth as
much as meat food and will not be extensively utilized until the
demand for meat scrap forces up the price to a point where the
casein can be sold more cheaply. Meat scrap, to be relished by the
chickens, must not be a fine meal, but should consist of particles
the size of wheat kernels or larger. The fine scrap gives the
manufacturer a chance to utilize dried blood and tankage which is
cheaper in quality and price than particles of real meat.
The last and least understood of the groups of food substances is
mineral substance or ash. Now, the chemist determines mineral
substance by burning the food and analyzing the residue. In the
intense heat numerous chemical changes take place and the substances
that come out of the furnace are entirely different from those
contained in the fresh food.
The lay reader will probably ask why the chemist does not analyze
the substances of the fresh material. The answer is that he doesn't
know how. Progress is made every year but the whole subject is yet
too much clouded in obscurity to be of any practical application. At
present the feeding of mineral substance, like the feeding of
protein, can best be learned by experimenting directly with the
foods rather than by attempting to go by their chemical composition.
In practice it is found that green feed supplies something which
grain lacks, presumably mineral salts. Moreover we know that such
food fed fresh is superior to the same substance dried. This may be
because of chemical changes that occur in curing or simply because
of greater palatability.
The other chief source of mineral matter is meat preparations with
or without ground bone. Recent experiments at Rhode Island have
attempted to show the relative value of the mineral constituents of
meat by adding bone ash to vegetable proteids, as linseed and gluten
meal. The results clearly indicate that mineral matter of animal
origin greatly improves the value of the vegetable diet, but that
the latter is still sadly deficient. Of course the burning process
used in preparing the bone ash may have destroyed some of the
valuable qualities of the mineral salts. Practically, we do not care
whether the value of animal meal be due to protein, mineral salts or
both.
In time the world will become so thickly populated that we cannot
afford to rear cattle and condemn a portion of the carcass to go
through another life cycle before human consumption. By that time
the necessary food salts will doubtless be known and we will be able
to medicate our corn and alfalfa and do away with the beef scrap.
The poultrymen will do well, however, not to count on the chemistry
of the future, for the chemist that makes the "tissue salts" for the
hen may manufacture human food with Niagara power and fresh eggs
will come in tin cans.
How the Hen Unbalances Balanced Rations.
Let the poultryman who figures the nutritious ratio of chicken feed
try this simple experiment. Place before a half dozen newly hatched
chicks a feed of one of the commercial chick feeds. When they have
had their fill, sacrifice these innocents on the altar of science
and open their crops. He will find that one chick has eaten almost
exclusively of millet seed, another has preferred cracked corn,
another has filled up heavily on bits of beef scrap and mica crystal
grit, while a fourth fancied oats and granulated bone. In short the
chick has, in three minutes, unbalanced the balanced ration that it
took a week to figure out. This experiment can be varied by placing
hens in individual coops and setting before each weighed portions of
every food in the poultryman supply man's catalogue.
There is only one kind of feeding that will balance rations and that
is to feed exclusively on wet mash. This is successfully done in the
duck business, but the duck is a Chinese animal and his ways are not
the ways of the more fastidious hen.
In dairy work the individual preferences of the cows are given
attention and their whimsy catered to by the herdsman. I know of
nothing that makes a man more feel his kinship to the beast than to
hear a good dairyman talk of the personalities and preferences of
his feminine co-operators.
With commercial chicken work, humanly guided individual feedings is
out of the question, though, if used, it might hasten the coming of
the two-egg-per-day hen. Individual feeding with the hen as sole
judge as to what she shall eat, which means each food in separate
hoppers and free range, is the best system of chicken feeding yet
evolved.
The duty of the poultryman is to supply the food, giving enough
variety to permit of the hens having a fair selection. In practice
this means that every hen must have access to water, grit
(preferably oyster shell), one kind of grain, one kind of meat, and
one kind of green food. In practice it will pay to add granulated
bone for growing stock. One or two extra grains for variety and as
many green foods as conveniences will permit to increase
palatability--hence increase the amount of food consumed, for a
heavy food consumption is necessary for egg production.
As corn is the cheapest food known, let it be the bread at the
boarding house and other grains the rotating series of hash, beans
and bacon. The grain hopper may have two divisions. The corn never
changes but the other should have a change of grain occasionally.
The extent of the use made of the various grains will be determined
by their price per pound.
The proportions of food of the various classes that will be consumed
is about as follows:
Of 100 lbs. of dry matter: 8 to 12 lbs. meat; 66 to 75 lbs. grain;
15 to 25 lbs. green food.
The profits of the business will be increased by supplying the green
food in such tempting forms as to increase the amount consumed and
cut down the use of grains.
The methods we have been describing in which various dry unground
grains, beef scrap and oyster shell, each in a separate compartment,
are exposed before the hen at all times, together with the abundant
use of green food, either as pasture or a soiling crop, is the
method of feeding assumed throughout this book.
The hopper feeding of so-called dry mash or ground grain mixture has
been quite a fad in the last few years. The tendency of the hens to
waste such food has occasioned considerable trouble. They are
picking it over for their favorite foods and trying to avoid
disagreeable foods. This difficulty is relieved when the food be
separated into its various components and the hen offered each
separately. As a matter of fact, there is no occasion for feeding
ground feed except in fattening rations and here the wet mash is
desirable.
The use of the products of wheat milling has been the chief excuse
for such practices, but unless these get considerably lower in price
per pound than corn they may be left off the bill-of-fare to
advantage. The great use made of these products in poultry feeding
was chiefly a result of the attempted application of the balanced
ration idea, but as has already been shown the efforts to raise the
protein ratio with grain foods is generally false economy.
The old-fashioned wet mash which the writer does not recommend
because of the labor involved, is, nevertheless, a fairly profitable
method of poultry feeding. It is used in the Little Compton district
of Rhode Island and was also used in the famous Australian egg
laying contests elsewhere described. Personally I would prefer
feeding ground grain wet, especially wheat bran and middlings, to
feeding it dry.
The scattering of grain in litter so generally recommended in
poultry literature is all right and proper, but is rather out of
place in commercial poultry farming. It is used on the large poultry
plants with the yards and long houses, but is not used on colony
farms or in any of the poultry growing communities. I should
recommend littered houses for Section 6 and the northern half of
Section 3 (see Chapter IV), but with warmer soils and climate where
the snow does not lie on the ground it would add a labor expense
that would very seriously handicap the business.
The systems of poultry feeding that are commonly advertised are
based either on some patent nostrum or a recommendation of green
food in novel form, such as sprouted oats. The joke about poultry
feed at 10 cents a bushel, absurd though it may seem, has caught
lots of dollars. To take a bushel of oats worth 50 cents, add water,
let them sprout and have five bushels costing 10 cents, is certainly
a wonderful achievement in wealth getting. The only reason a man
couldn't run a soup kitchen on the same principle is that he can't
do a soup business by mail. Sprouted oats are a good green food,
however, though somewhat laborious to prepare. I should certainly
recommend them if for any reason the regular green food supply
should run out.
The points already mentioned are about all the practical suggestions
that the science of animal nutrition has to offer the poultryman.
The discussion of feeding from its technical viewpoint is
sufficiently covered in the chapter on "Farm Poultry" and the
discussion of the management and economics of various types of
poultry production.