Physiological response of broiler embryos to different incubator temperature profiles and maternal flock age during incubation. 1. Embryonic metabolism and day-old chick quality.

Broiler strain, maternal age, and incubation temperature influence embryo metabolism. Hatching eggs were obtained from young (Y; 28 to 34 wk, $\bar{\rm x}$ = 31.2 wk), mid (M; 36 to 45 wk, $\bar{\rm x}$ = 40.

The effect of maternal canthaxanthin supplementation and hen age on breeder performance, early chick traits, and indices of innate immune function.

Hen age and nutrition influence chick innate immunity. The immunomodulatory antioxidant carotenoid canthaxanthin is transferred from the hen diet to the egg. Antioxidants could protect the chick from bactericidal oxidative species produced by the immune system.