Cause of Hen-Feathering in Campine and Bantam Males.

Abstract

In ordinary breeds of the fowl differences in secondary sexual characteristics of the plumage have been shown 1 to be due to endocrine factors which are largely controllable under experimental conditions. With the type of feather produced serving as a measure of response, evidence from various sources is consistent in indicating that in most breeds the follicles of the male and those of the female react in exactly the same manner to any set of stimuli. 2 In other words, sexual differences in plumage are referable to differences in endocrine stimuli rather than to differences in tissue response. Since this situation obtains in ordinary breeds of fowl, it has been natural to look for an endocrine causation of hen-feathering in those strains where the male has a plumage similar to that of the female. The prompt assumption of male plumage by the castrated Sebright, 3 which is normally hen-feathered, seemed at first to supply definite evidence of an endocrine causation for hen-feathering in the male. But cross-transplantation of testes in Sebright and Leghorn fowls 4 showed that the testes of hen-feathered Sebrights produce no special hormone different from that of cock-feathered Leghorns; and the experiments to be reported at this time indicate that follicles from a hen-feathered strain and those from a cock-feathered strain may produce their respective types of feathers when grown side by side and subjected to the same endocrine environment.