Evaluating light spectrum and intensity for female turkey breeder reproductive performance

Turkey hen reproductive cycles are short with a low peak, making environmental management, including lighting programs, especially important for sustaining production. Although high light intensities are typically used to improve performance, this practice lacks strong support from the scientific literature. Evidence from other avian species suggests red light more effectively stimulates the reproductive axis, but light intensity may confound this response. We aimed to evaluate the effects of red spectrum (R) or white (W) lighting at high (H, 0.3 W/m²) or low (L, 0.1 W/m²) intensity on reproductive parameters. A total of 402 grandparent-line Hybrid Converter hens were reared at a commercial facility before random allocation to 24 experimental pens within four rooms at 19 weeks of age (woa). Light spectrum was assigned by room, and all birds were exposed to their respective color treatments at L intensity throughout rearing. At 30 woa, intensity levels were assigned by pen for a two-factor split-plot arrangement (n = 6/spectrum-intensity combination), and the hens were photostimulated (13.5L:10.5D). Management adhered to commercial guidelines, and eggs were collected twelve times daily until 60 woa. Light treatment did not affect estradiol profiles or cumulative egg production, suggesting high intensity lighting may not be necessary to optimize performance. However, both H intensity and R color treatments synchronized oviposition patterns, with eggs laid more frequently during the daily peak. Egg weight increased with L intensity treatment, which was in line with a tendency for increased body weight (BW) and relative abdominal fat pad weight. Reduced BW uniformity with H intensity treatment suggests these differences in BW were related to changes in behavior, but individual responses were variable. Based on these findings, each of our treatments provided lighting conditions sufficient to initiate and sustain egg production. However, light spectrum and intensity can be manipulated to influence oviposition timing and egg quality, highlighting opportunities for targeted breeder management strategies.