The Optimum Protein Level for Chickens as Influenced by Sex

THE growth response of chickens as related to quality and quantity of protein in the ration has been studied at this station for several years. In one phase of this work, growth curves of males and females consuming rations of different protein levels were compared to ascertain if the maximum increment of growth occurred at the same protein level for the two sexes. Irwin and Kempster (1942) report two trials in which “it is apparent that on the basis of growth experience the male chickens utilized the additional protein to a better advantage than was the case of the female chicken fed the same ration.” However, they make no comment on the optimum level of protein for males and females. The experiments reported here were planned to ascertain if male chickens can still further increase their gains on a higher protein level after the females have reached their greatest response. . . .