38 



Genetic Studies in Poultry 



illustrated volume on his work (1919), it is unnecessary for us to give 

 more than a brief account of our experiments, pointing out wherein 

 they agree with his^ and wherein they differ. 



Experimental data. 



Our F^ birds were bred from two Silver Sebright hens and a Gold 

 Pencilled Hamburgh cock. Of the eight ^i cockerels reared (which of 

 course were all Silvers), five were fully hen-feathered^ (cf Text-fig. 1), 

 two were cock-feathered (cf Text-fig. 2), and one was intermediate, 

 though with a pronounced tendency to the henny type. To the nature 

 of such intermediates we shall recur later. The Sebright hens were 



Text-fig. 1. Henny F^ ^ (ex Sebright x Hamburgh) Text-tig. 2. Normal feathered Fi ^ (ex Sebright x Hamburgh) 



not tested separately, but it is clear that one of them, at any rate, must 

 have been heterozygous. The indication that henny feathering behaves 

 as a dominant to normal cock feathering was confirmed by the results 

 obtained in 1912 and in subsequent years. During the period 1912 — 

 • 1919 we raised 463 male birds from birds heterozygous for henny 

 feathering mated with birds known not to carry the henny factor. 

 These 463 cocks fell into two distinct classes, viz. those normally 

 cock-feathered, and those which were either fully hen-feathered or 

 intermediate. For reasons that are given below (p. 42) the inter- 

 mediates are to be regarded as hen-feathered birds. As is shewn in 



1 The parents and various progeny from this cross are figured in this Journal, Vol. iv. 

 1914, PI. 4. 



