Leyk, Curtis A., D.V.M., Aaron Stephan, Ph.D., and Jack Tieberg, B.S.; Biological Research and Development, ONCE Innovations/Signify, Plymouth, MN
Lighting represents a promising management tool to improve the well-being of poultry. To date, most studies that compared lighting conditions on broiler welfare outcomes have evaluated individual lighting variables (spectrum, intensity, or schedule), and few studies have compared to conditions used widely in commercial environments. The objective of this study was to find an optimal light recipe for raising broiler chickens, increasing the welfare of the birds without negatively impacting the production parameters. The study was conducted at the ONCE Research Facility and three commercial producers. In each trial a test light recipe was formulated by defining spectrum, schedule, and/or intensity and compared to the standard light recipe used at the facility. In the case of the ONCE Research Facility, 500 Ross 308 or 708 chicks were divided between 10 rooms - 5 rooms utilizing the novel light recipe and 5 with a standard light recipe. Weights and FCR were monitored regularly and welfare measurements were conducted between production days 35 and 55. The welfare measures included: Blood samples for Heterophil:Lymphocyte (H:L) Ratios, Inversion Test, Isolation Test, Emergence Test, and Tonic Immobility. In the commercial trials, broilers were raised according to the integrator’s standard protocol, with 2 houses utilizing the novel light recipe and 2 control houses, using flock-source matched chicks. Each house contained between 19,200 and 26,300 birds. Similar welfare tests were conducted, and the integrator’s settlement data were used to evaluate production parameters. Student’s t-test and two-way ANOVA were used to compare outcomes of each test between light treatment groups. The initial three trials at the ONCE Research Facility indicated that broiler production was improved when using a specific Red:Green:Blue ratio during the brood phase and a distinct Red:Green:Blue ratio during the grow phase. This optimized recipe, which will be described, was subsequently evaluated in additional trials at the ONCE Research Facility and 6 trials at commercial sites, showing improved welfare. Results of each trial will be presented, showing a statistically significant improvement (p<0.05) in 6 of 7 Inversion Test, 4/7 Emergence Tests, 7/7 Isolation Test, 6/7 Tonic Immobility, 4/4 Avoidance Distance Test, and 1/8 H:L Ratio. The results of this multi-site and multi-flock trial indicate that the welfare of broiler chickens can be improved by utilizing an optimal lighting recipe.
