GENETIC STUDIES IN POULTRY. 

 III. HEN-FEATHERED COCKS. 



Bv R. C. PUNNETT, F.R.S., 

 AND THE LATE Major P. G. BAILEY, R.F.A. 



(With two Text-figures and Plates VII— XI.) 

 CONTENTS. 



PAGE 



Introduction ........... 37 



Experimental data 38 



Intermediates 41 



Colour of Intermediates 44 



The hypothesis of complementary factors 48 



Castration experiments (performed by Dr F. H. A. Marshall) . . 49 



General discussion 51 



Note on the sex-proportions and ratio of henny to normal cocks . 54 



Tables 55 



Explanation of Plates 56 



References 57 



Introduction. 



In certain breeds of poultry, notably in the Sebright Bantam, in 

 Henny Game, and in certain strains of Campines^, the cock is nor- 

 mally feathered like the hen. The hackles, saddle feathers, and the 

 feathers of the tail in such henny cocks are of the form of the cor- 

 responding feathers in the female, a peculiarity which will be found 

 illustrated in any of the standard works on poultry. In 1911 we started 

 to investigate the genetics of hen-feathering in the male bird, making 

 use of the Silver Sebright Bantam as our hen-feathered breed. It 

 happened that Prof Morgan in America started some similar experi- 

 ments in the same year. As he has recently published a sumptuously 



1 Heuny cocks may occasionally occur in other breeds. Lamon and Slocum figure a 

 henny Silver Wyandotte and a henny Silver Spangled Hamburgh ; and it is well known 

 that they may occur in Pencilled Hamburghs (see Plate IX). 



