The Endocrine Secretion of Hen-Feathered Fowls

In the older literature there are many references to changes that have been noticed in old hens and female pheasants that make these birds more like the males of their species. They become quarrelsome, they sometimes crow, the feathers change their color, etc. It has been recorded in several cases that these changes appear after the female has ceased to lay, and in a number of cases that the change was associated with a diseased condition of the ovary. Complete removal of the ovary of birds is a difficult operation owing to its irregular shape and to its close adherence to the body wall. Goodale has succeeded, nevertheless, in completely removing the ovary of young fowls. When the adult plumage develops in such birds it is like that of the cock of their breed. In the Leghorns, where the difference between the sexes is very great, the result is most striking. The comb and wattles, and the spurs also, grow larger than in the normal hen. Evidently something produced by the ovary—some internal secretion perhaps—inhibits the full development of the plumage of the hen, of her comb, and sometimes also of her spurs.