Blue light during rearing: does it impact the health and production of leghorn pullets and hens?

ABSTRACT Aggression and cannibalism in table egg laying birds are major welfare concerns. Use of blue light has been shown to have a calming effect on broilers. However, because of its short wavelength, blue light may delay sexual maturation in reproductive birds. An objective of this study was to assess how blue light, with intensity corrected for avian vision, provided during the pullet phase, impacted the production of Lohmann pullets and hens. The 3 light treatments studied were white light to 17 wk (W17), blue light (peak 455 nm) to 17 wk (B17), or blue light to 15 wk followed by 2 wk of white light (B15). Body weight, uniformity, feed disappearance, mortality, and ocular measurements were assessed during the pullet phase (0-17 wk) and body weight, feed intake and efficiency, egg production and quality, and mortality were measured during the hen phase (17-53 wk). Two Lohmann strains, LSL-Lite and Brown-Lite, were studied (n=1,800 per strain). Two replicate trials using a 3 × 2 factorial arrangement in a randomized complete block design were performed. Each trial included 6 rooms with 6 pens/room (3 pens/strain). Data were analyzed using Proc Mixed (SAS 9.4), and significance was declared when P ≤0.05. The B15 and B17 treatments were combined into one treatment (Blue), before being separated at 15 wk when B15 rooms switched to white light for the remaining 2 weeks. In the hen phase, only white light was provided. Pullets were heavier under Blue at 4 wk ( P <0.01). Pullets in the W17 treatment had greater feed disappearance from 4-8 wk ( P <0.01). Light did not affect any eye parameters; however, eye weight and anterior-posterior diameter were increased in the LSL-Lite strain. Light had no effect on age at first egg, egg production or quality, or hen mortality. To conclude, blue light during pullet rearing had no lasting impacts on body weight, feed intake, ocular measures, or overall mortality.