Effect of pre-incubation and incubation conditions on hatchability, hatch time and hatch window, and effect of post-hatch handling on chick quality at placement

The zootechnical performances of broilers at the end of the rearing period depend in part on the quality of day-old chicks at placement. The quality of day-old chicks is highly affected by the incubation conditions, by hatch time (which determines the time spent in the hatcher under high temperature and humidity), and by the handling of chicks after hatch. This article first presents an overview of the most relevant pre-incubation factors that affect chick quality: egg size, egg weight, quality of eggs, sex of embryos, age of breeders, and conditions and duration of egg storage. It then reviews the most important incubation factors that affect hatch time, hatchability and hatch window (temperature, humidity, turning, ventilation and concentration of gases). Finally, the effect of early post-hatch handling (including processing and especially transportation of chicks) as a possible source of stress influencing the quality of chicks at placement is discussed.