Research Note: Effects of different light-emitting diode lights during egg incubation on hatching performance and embryo development in White King pigeons.

The light provide during incubation can influence hatching characteristics (hatching time, hatchability, etc.) and embryo development in chickens, geese, and turkeys. However, relevant studies on this factor in pigeons are lacking. This study investigated the effects of in ovo photostimulation during embryogenesis on hatching performance, squab quality, and embryo development in pigeons. 400 eggs from paired- bred pigeons were randomly distributed into 4 incubation lighting treatments, with 2 replicates per treatment. The treatments included dark as a control (NL), 12-h light, and 12-h dark photoperiods of white light (WL), red light (RL), and green light (GL) (100 lx at egg level) during the first 15 d of incubation. A total of 1,600 eggs in 4 batches from White King pigeons were used. The results showed that hatching time of the WL group was significantly shorter than that of the dark light group (P < 0.05). The hatchability of fertile eggs in the WL group was significantly higher (P < 0.05), whereas the hatchability of fertile eggs in the RL group was significantly lower (P < 0.05) than that of in the control group. Light stimulation had no effect on time to 90% hatching or average hatching time (P > 0.05). In addition, the hatch window was not extended by light stimulation (P > 0.05). The group incubated under GL showed an increase in embryo weight and relative leg muscle on embryonic d 14 and the hatching day compared to the dark incubation (P < 0.05). Green light stimulated the heart and liver development during the early and middle stages of embryogenesis. It was concluded that white light stimulation during embryogenesis accelerated the hatching process, whereas monochromatic green light had a positive effect on embryo development. Our findings provide important guidance for developing light protocols for pigeon egg incubation.