Functional Effects of Single-Stage vs. Multi-Stage Incubation Systems and Parental Flock Age on Embryonic Development, Oxidative Stress, and Performance of Male Broiler Chickens

It is well established that both the age of the breeder hen and the type of incubator can influence the efficiency of the hatching process. However, there is a lack of information in the literature regarding the interaction between these two factors. This study evaluated the effects of incubator type (multi-stage vs. single-stage) and breeder hen age (35 and 61 weeks) on the hatching parameters, embryonic oxidative stress, performance, carcass yield, and meat quality of male broiler chickens. The embryo livers from the multi-stage incubator presented significantly higher NADP oxidase (NOX) values (p = 0.022), indicating elevated oxidative stress. A significant interaction between breeder age and incubator type was observed for the thiol concentrations, with embryos from older hens incubated in the multi-stage system showing higher thiol levels compared to those from the single-stage system. Birds from these older breeders demonstrated increased breast yield, feed intake, and weight gain, without significant changes in feed conversion ratio. Additionally, the single-stage incubator was associated with reduced embryonic oxidative stress, lower egg weight loss during incubation, and improved early performance of chicks during the first week post-hatch. In conclusion, beyond the previously recognized benefits of single-stage incubation systems, our findings highlight their potential to mitigate oxidative stress in embryos, thereby enhancing early chick development.