When two crested canaries are bred together some of the chicks will be
permanently bald. Another cause, apparently, is the tendency for some
birds to constantly rub their heads against the perch or bars of the
cage. This condition is sometimes accompanied, or perhaps caused by the
presence of lice.
Sometimes baldness is caused by an incomplete moult, the lost feathers
not having been replaced during the regular moulting season. Sometimes
severe changes in the weather during the moult, or food deficiency
during the moult is the cause of incomplete feather growth.
There is no treatment for inherited baldness. If lice or mites are
present, treat the bird as indicated under "Mites." See that the bird
has a normal seed diet with plenty of greens, a cuttle bone in the cage,
plus egg food and moulting food two or three times each week. Allow the
bird to exercise as much as possible, and there is a good chance that
during the next regular moult the feathers will return.