LAUSR

&NA; 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. Broiler breeder hen diets were supplemented with 0 (Control), 6 (Low), or 12 (High) mg/kg canthaxanthin. Chick early growth and ex vivo innate immunity were measured at 31 to 33 (Early), 45 to 47 (Mid), and 57 to 59 (Late) wk of hen age. Escherichia coli (E. coli) bactericidal capacity, phagocyte activation (number of phagocytes containing at least one E. coli), phagocytic capacity (number of phagocytes containing one or more E. coli), and oxidative burst at 1 and 4 d of age were determined. Egg and chick liver canthaxanthin and chick plasma total antioxidant capacity were measured. Differences were considered significant at P ≤ 0.05. Breeder productivity was greatest for the Low hens; diet did not affect egg yolk, albumen, or shell proportions. Egg canthaxanthin increased with maternal supplementation and plateaued after 28 days, but was not affected by hen age. Chick liver canthaxanthin increased with maternal supplementation, but decreased as hens aged. Hen diet did not affect broiler chick performance to 21 days of age. Maternal canthaxanthin at 6 mg/kg increased chick E. coli bactericidal capacity and d 1 oxidative burst; phagocytosis was unaffected. E. coli bactericidal capacity decreased as hens aged, but increased from 1 to 4 d, indicating maturation of chick innate immunity. Plasma total antioxidant capacity at d 1 increased with maternal canthaxanthin in chicks from Mid and Late hens. Canthaxanthin possesses immuno‐modulatory and antioxidant properties, and hen age affected chick innate immune development. Single‐comb White Leghorn hens were fed the same levels of canthaxanthin to determine the rate of incorporation into eggs. Egg canthaxanthin reached a plateau after 7 d. Canthaxanthin in the hen diet at 6 mg/kg resulted in the greatest positive effect on hen performance, with little effect on the chick.