ADAPTATION OF LAYING HENS TO A 23.5 H LIGHT-DARK CYCLE

Oviposition times, egg number and egg weights were recorded in laying hens from three selection lines kept under normal (16L:8D) and short ( 16L:7.5D) light-dark cycles. Individuals capable of producing eggs mor e frequently than every 24 h were revealed in the short-cycle environm ent. Most of them belonged to a line selected for egg number. With inc reasing age, the adaptability to the short-cycle environment decreased .