Effects of eggshell temperature pattern during incubation on primary immune organ development and broiler immune response in later life

Abstract Eggshell temperature (EST) during incubation greatly affects embryo development, chick quality at hatch, and subsequently various broiler physiological systems. Until now, a constant EST of 37.8°C seems optimal. Data on effects of EST patterns on immune organ development and subsequent broiler immune response are, however, scarce. A higher EST of 38.9°C in week 2 and/or a lower EST of 36.7°C in week 3 of incubation potentially positively affect embryo immune organ development and broiler immune response post hatch. Broiler eggs (n=468) were incubated at 4 different EST patterns (n=117 eggs / treatment) from week 2 of incubation onwards. EST week 1 (embryonic age (E)0