The effect of parachlorophenylalanine and active immunization against vasoactive intestinal peptide on reproductive activities of broiler breeder hens photostimulated with green light.

Photostimulation of retinal photoreceptors appears to inhibit reproductive activity in birds. In the present study, the involvement of serotonin and vasoactive intestinal peptide was investigated in relation to reproductive failure associated with retinal photostimulation. Hens at 23 wk of age were divided into six rooms equipped with individual cages.