INBREEDING IN RELATION TO EGG PRODUCTION 283 



haK-brother-sister matings. Inbred pen 2, with progeny largely from sire-on- 

 daughter matings, gave equality of sexes. In inbred pen 3 where inbred lines 

 were crossed there occurred a low sex ratio which has been characteristic of close 

 inbreeding. 



These data appear to indicate that inbred male chicks are less able to survive 

 than are female chicks. Such a difference probably arises from more vicious 

 fighting among males than among females. Inbred males are probably less 

 vigorous than ordinary production-bred males with which they run and many 

 succumb in the struggle. 



