Exposing broiler eggs to green, red and white light during incubation

Previous work has shown that exposing broiler eggs to white light during incubation can improve hatchability and post-hatch animal welfare. It was hypothesized that due to how different wavelengths of light can affect avian physiology differently, and how pigmented eggshells filter light that different monochromatic wavelengths would have differential effects on hatchability and post-hatch animal welfare indicators. To determine, we incubated chicken eggs (n = 6912) under either no light (dark), green light, red light or white light; the light level was 250 lux. White and red light were observed to increase hatch of fertile (P < 0.05) over dark and green light incubated eggs. White, red and green light exposure during incubation improved (P < 0.05) the proportion of non-defect chicks over dark incubated eggs. Post-hatch 45-day weight and feed conversion was not affected by light exposure of any wavelength (P > 0.05). Fear response of during isolation and tonic immobility was reduced (P < 0.05) in broilers incubated under white or red light when compared with either green or dark broilers. Broilers incubated with white or red light had lower (P < 0.05) composite asymmetry scores and higher (P < 0.05) humoral immunity titers than dark incubated broilers, however, green light broilers did not differ (P > 0.05) from dark incubated broilers. All light incubated broilers had lower (P < 0.05) plasma corticosterone and higher (P < 0.05) plasma serotonin concentrations than dark incubated broilers. These results indicate that white light and red light that is a component of it are possibly the key spectrum to improving hatchability and lower fear and stress susceptibility, whereas green light is not as effective. Incubating broiler eggs under these spectrums could be used to improve hatchery efficiency and post-hatch animal welfare at the same time.