Cloacal feather trimming improves reproductive performance of layer breeder roosters

Brazil is among the world's leading egg producers and currently has 1.4 million-layer breeders. Although genetic selection has improved reproductive traits more significantly in layer breeders than in their broiler congeners, aging is still an element that greatly affects fertility and hatch rate. Therefore, strategies to minimize age-related losses are crucial in the routine of layer breeder farms. Here, we assessed the effects of cloacal feather trimming (CFT) on reproductive parameters of a commercial-flock performing natural mating. To this end, a parent-stock house accommodating 11,238 hens and 1230 roosters was divided into 6 compartments, where 3 compartments containing roosters subjected to monthly CFT were interspersed with 3 compartments containing intact roosters. From 35 to 77 weeks of age, 2880 eggs from each group were collected every 40 days, marked and placed back with the rest of the eggs to undergo the company's standard procedures. Afterwards, unhatched eggs from the two groups were subjected to embryodiagnosis. Aging had an impact on all the parameters evaluated, while CFT reduced infertility and early embryonic mortality, improving hatch rate and hatchability. Interactions between CFT and age were observed for infertility and early embryonic mortality. From 41 to 77 weeks of age, infertility in the CTF group decreased between 0.9 % and 3.3 % in relation to control group, whereas hatch rate increased between 2.6 % and 4.3 %. These findings indicate that a simple management such as CFT can significantly benefit the production of breeding flocks, and can be applied to the routine of parents, grandparents and great-grandparents.