Effect of hatching conditions on indicators of welfare and health in broiler chickens

On-farm hatching of broiler chickens is increasingly applied, because farmers report improved performance compared to broilers hatched at the hatchery. However, there is little scientific evidence for these effects. Aim of the study was to find evidence for long-lasting effects of hatching conditions on performance and welfare of broiler chickens. Broilers hatched at the hatchery (n=16 control flocks) or on-farm (X-treck system, n=16 flocks). Each X-treck flock was paired to a control flock from similar parent stock, reared in identical houses and subjected to similar management. In the X-treck, eggs are transferred to the stable at d18 of incubation and hatch in the stable. Chicks have immediate access to feed and water. Chicks from the hatchery received their first feed and water when they arrived at the farm. Indicators of welfare were measured at d0 (arrival of hatchery chicks), d21 and just before slaughter. Analysis of variance was used to test effects of treatment and age; data were transformed if necessary. X-treck broilers were heavier at d0 compared to control broilers (P<0.01) due to immediate access to feed and water after hatching. Quality of X-treck chicks was impaired compared to control chicks, as indicated by on average a worse navel and leg quality (P=0.01), which might be due to selection of chicks at the hatchery, which did not happen in the X-treck system. Control chicks showed a more stressful response (more vocalisations) in a novel environment test at d0 compared to X-treck chicks (P<0.01), but there were no treatment differences at d21. No treatment differences in gait score at d21 and at slaughter age were found, indicating that hatching conditions did not affect lameness. X-treck broilers had less foot pad dermatitis at d21 and slaughter age (P<0.05) and had numerically better hock burn scores at slaughter age than control broilers (P=0.56). X-treck broilers were more dirty at d21 and at slaughter age than control broilers (P=0.08). Litter quality was better in X-treck houses than in control houses, which seems to be in contradiction to bird cleanliness but in agreement with foot and hock scores. Farm records of the majority of flocks indicated a lower rejection rate at slaughter and a lower mortality for X-treck flocks compared to control flocks, although these figures need to be confirmed in the final analysis. Thus, first results of this study indicate that effects of hatching conditions on welfare of broiler chickens may indeed be long-lasting.