Impact of light spectrum electromagnetic radiation variations on performance and hormonal profiles in laying hens

Avian photopic curves show energy peaks at different wavelengths than humans, particularly in the ultraviolet, yellow, and red range. Therefore, an illumination system with a spectrum tailored for laying hens, encompassing the entire visible spectrum, can enhance performance and welfare. The primary contribution of this study was the development of two Spectral Power Distributions (SPDs) specifically designed for laying hens, with different spectral proportions (S1 and S2), and the evaluation of their effects on productive performance, egg quality, and hormonal levels, compared to conventional white lighting at 3000 K (C). The SPD with a higher emission of red light to increased egg production and egg mass. It also had a lower melatonin concentration, suggesting an inverse relationship with the egg production rate. Regarding egg quality, SPDs specifically designed for laying hens resulted in eggs with greater weight (S1), shell strength (S2), and yolk height (S1 and S2) and diameter (S2). The study's results indicate that lighting emitting wavelengths within the spectrum visible to poultry, with higher emissions at long wavelengths, appears to be more favorable for laying hens than conventional lighting. A spectrum with higher emissions at shorter wavelengths appears to impair the productive performance of laying hens.