THE IMPACT OF LIGHTING PROGRAMS ON POULTRY HATCHING TRAITS: REVIEW

Lighting programs during incubation—encompassing photoperiod length, light color/wavelength, and intensity—play a pivotal role in avian embryogenesis, hatchability, and post-hatch performance. This review synthesizes findings from studies to evaluate how these variables influence hatching traits (hatchability, embryonic mortality, chick quality) and physiological outcomes (hormonal profiles, stress indicators) across poultry species. Evidence suggests that significantly influence poultry hatching outcomes. Intermediate photoperiods (12–16 hours of light) enhance hatchability (up to 92%), synchronize hatching, and reduce stress hormones (e.g., corticosterone) in broilers and turkeys, while continuous light (24L) risks thermal stress. Green light (560 nm) promotes muscle growth via melatonin-mediated satellite cell proliferation and improves hatchability (94% in broilers), whereas red light increases malformations in turkeys. Moderate light intensity (20–40 lux) optimizes chick quality (e.g., navel closure, skeletal development), while high intensity (>60 lux) elevates embryonic mortality. Species-specific responses exist: green light benefits broilers but not layers, and red light harms turkeys but not quails. Conflicting results arise from genetic differences, eggshell pigmentation, and light source variability (LED vs. fluorescent). Standardized protocols and multifactorial studies are needed to refine lighting strategies for improved productivity and welfare.