The effect of a photoperiodic green light program during incubation on embryo development and hatch process

Abstract

This study was conducted to evaluate the effect of a 12 hours light, 12 hours dark  (12L:12D) photoperiod of green light during day 1 to day 18 of incubation time, on embryo growth, hatch performance and the hatch process. In the light-stimulated group, the monochromatic light was provided by a total of 204 green LEDs (522nm) mounted in a frame which was placed above the eggs to give even spread of illumination. The control group was incubated in complete darkness. Four batches of eggs (n=300 per group per batch) from fertile Ross 308 broiler breeders were used in this experiment.  The beak length and crown-rump length compared of embryos incubated under green light were significantly longer than those incubated in the dark condition at day10and day 12, respectively (P<0.01). Furthermore, green light exposed embryos had a longer third toe length compared to control embryos at day 10, day14 and day17 (P=0.02).  At the group level (n=4 batches), light stimulation had no effect on chick weight and quality at take-off, the initiation of hatch and hatch window. However the individual hatching time of the light stimulated focal chicks (n=33) was 3.4h earlier (P=0.49) than then control focal chicks (n=36). The results of this study indicated that green light accelerated embryos development and resulted in an earlier hatching.