42 Genetic Studies in Poultry 



(2) Nevertheless all of these grades of intermediates behave alike 

 in one respect. At the first moult they all become fully henny, or nearly 

 so. We have now kept some dozens of intermediate birds over their first 

 moult without meeting any exception to this rule. In some cases the 

 change to henny feathering is complete. As a typical example we may 

 take the case of ^ 105/18 (PI. VII, fig. 1). A full henny cock {^ 90/17 in 

 Exp. 44) was mated in 1918 to a Brown Leghorn hen. Only two male 

 chicks were reared, viz. j/ 104/18 and c^ 105/18. These two birds grew 

 up so closely alike that they were indistinguishable in appearance. They 

 were clear golds with traces of brown occurring in some of the quills and 

 in the feathers at the base of the tail. Both were so like normal males 

 in appearance that one of them, cT 104, was kept, and has now moulted 

 twice. In 1919 all of his new feathers were purely henny, as shewn 

 on PI. VII, fig. 2\ At this period however he was not full henny in 

 appearance because some of the old intermediate feathers were not shed 

 until the following year. By the second moult these worn feathers, 

 which had survived from the original plumage, were all shed, and the 

 bird is now fully henny. Noteworthy is the considerable development 

 of melanic pigment in the saddle feathers which has accompanied the 

 structural change. 



Another good example of the change from intermediate to henny 

 feathering at the moult is illustrated on PI. X. Two brothers of inter- 

 mediate plumage were closely similar, both in colour and in the nature 

 of their feathering. One of them (Fig. 1) was killed at nine months old ; 

 the other was kept for a year longer, until he was over his first moult 

 (Fig. 2). This case differs from the preceding one in that the plumage 

 did not become fully henny. Some of the feathers shew traces of the 

 intermediate condition, but the change as a whole is sufficiently striking. 

 Genetically these two birds were silvers. 



(3) Although intermediate birds always moult out henny, in so far 

 as our experience goes, they may sometimes revert to the intermediate 

 type at some later moult. In illustration of this we may take the history 

 of (^ 201/14, who was bred in Exp. 28. In his first plumage he was 

 intermediate, with a marked tendency towards normal cock feathering. 

 The sample of his feathers taken in 1914 is unfortunately lost, but they 

 were very like those of {/ 126/15 (from Exp. 15) shewn on PI. VIII, fig. 1. 



1 The bird recorded by Darwin (A. and P., i. p. 258) "which, after assumiug its 

 perfect masculine plumage, became hen-feathered in the autumn of the following year " 

 was doubtless an intermediate with a pronounced tendency to normal feathering in its 

 first plumage. 



