Pleiotrophic effects of the sex-linked delayed feathering gene, K-n, in the chicken.

In several series of comparative measurement studies the effect that the sex-linked delay feathering (K-n) gene had on comb and uropygial gland development was measured in chickens from two to 60 weeks of age. The gene's effect on heart, adrenal gland and reproductive organ weights were also determined. The comb and uropygial gland size differences were very dramatic throughout the whole age range. Combs of mutant birds were greatly reduced in size while the uropygial glands were greatly hypertrophied. Heart and adrenal gland weights were also significantly increased in the mutant birds. Gonad weights however showed no difference. Responsiveness of mutant chick's combs to injections of testosterone propionate was also tested and shown to have a response similar to that of non-mutant chicks.