THE EFFECTS OF LIGATING THE TESTES OF 

 HEN-FEATHERED COCKS. 



T. H. MORGAN. 



It has been shown that when hen-feathered males of certain 

 races of poultry (Sebrights, Campines) are castrated the new 

 feathers have the characteristics oi the cock-feathered males. 

 The operation of castration is dangerous for adult birds with 

 large testes because the birds often die from haemorrhage from 



FIG. i. Sebright whose testes had been tied off September 29, 1919; the pho- 

 tograph was taken April 8, 1920. 



the spermatic blood vessels, yet in order to be certain that a 

 cockerel is going to be hen-feathered it is necessary (except when 

 races pure for hen-feathering are used) to operate on adult 

 birds. As these are often too valuable to risk the chances of an 

 unsuccessful operation I have tried to find out whether the same 



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