Behavior of broilers and impacts occurring to them during mechanical loading under field conditions

Mechanical loading has been used increasingly in recent years alongside the manual loading of broilers. The aim of this study was to analyze the influence of various factors on the behavior of broilers and the impacts occurring to broilers during loading with a loading machine in order to identify risk factors and thus improve animal welfare. During 32 loadings we assessed escape behavior, wing flapping, flip, bumping into an animal, and bumping against the machine or container by evaluation of video recordings. The parameters were analyzed for influences of rotation speed, container type (GP container vs. SmartStack container), husbandry system (“Indoor Plus” vs. “Outdoor Climate”), and season. In addition, the behavior and impact parameters were correlated with the loading-related injuries. The results showed that an increase in rotation and conveyor belt speed was associated with an elevated risk of all behaviors or impacts, except for a lower risk of escape behavior. The seasonal influence showed that the risk of wing flapping, bumping into an animal, and bumping against the machine or container was highest in fall. The comparison of the container types showed that the risk of escape behavior, wing flapping, and bumping into an animal was increased when loading with the SmartStack container, but the risk of bumping against the machine or container was reduced. For animals of the husbandry system “Outdoor Climate,” the risk of bumping into an animal and bumping against the machine or container was reduced. In addition, we found an influence of the examined parameters on the loading-related injuries. Increased escape behavior reduced the risk of severe injuries (fractures, dislocations, epiphysiolyses). Wing flapping and bumping against the machine or container increased the risk of hematomas and abrasions. The risk of hematomas was increased if broilers bumped into conspecifics. In summary, our analysis revealed that the behavior and impacts on the animals during loading are influenced by each of the analyzed factors and that they in turn can affect loading-related injuries.