Commingled or sex-separate rearing on body composition, testicular development, and reproductive performance of broiler breeder cockerels

Over the years, achieving the reproductive potential of broiler breeders has become a challenge as they share the same growth potential of their offspring. As males with increased body and breast weight are less likely to efficiently mate, it is suggested to raise cockerels separate from pullets (SS) instead of commingled (CO) as it better facilitates the control of BW gain and the overall growth potential. However, due to the lack of knowledge surrounding the impact SS and CO rearing have upon broiler breeder performance, more research is required. The objectives of this study were to compare the BW, BW uniformity, testicular development, growth performance, and reproductive performance of broiler breeder males when reared SS or CO. Our results indicate that indirect feeding of CO males led to poor BW uniformity and decreased fertility towards the end of lay as well as increased the mortality rate of roosters during the laying period. However, direct feeding of sex-separate males was found to improve BW uniformity. The enhanced ability to control the sex-separate male’s growth along with more productive semen production as indicated by the wider seminiferous tubules and more Sertoli cells could explain the improvements observed in fertility towards the end of lay.