Daylength and its impact on turkey welfare and productivity

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Daylength plays can play an important role in poultry production, but research on turkeys is not adequate and therefore not predictive of optimum levels required by modern genotypes. Research at the University of Saskatchewan has established the importance and impact of daylength on the performance and welfare of broiler chickens. In turn, this information permitted standards to be set by industry and government that meet the bird's requirements and improve both welfare and productivity. Although biologically similar, turkeys are a different genus and species and have a different production lifespan. Therefore the results in broiler chickens may not hold true in turkeys. For instance, our research demonstrates a significant impact of daylength on welfare in the short life cycle (31 to 49 days) of broiler chickens and it can be predicted that the detrimental impact of improper daylength use on turkeys, which are kept much longer (12 to 20 weeks), could be significantly larger. Therefore, the objective of this work is to determine the impact of daylength on turkey welfare and productivity. To allow us to do this, graded levels of daylength (14L:10D, 17L:7D, 20L:4D and 23L:1D) will be used to establish response curves for all variables measured. To help answer the questions of welfare and productivity, response criteria will include growth rate (productivity measure but may also give us clues regarding welfare), feed intake, feed efficiency, mortality (important for both productivity and welfare determination), the causes of mortality (each bird that is culled or dies will be posted for cause of death), mobility within the flock (productivity, welfare - measured by gait score), behavioural output, behavioural rhythms, physiological rhythms (melatonin), ocular size and weight, and eye health. A total of 2 room replications per experiment for lighting program will be included (sex separate penning within each room), and the experiment will be completed twice to allow appropriate replication. This research should permit industry and government to set appropriate daylength standards for turkey production in Canada and elsewhere in the world.