The welfare impacts of mechanical and manual broiler catching and of circumstances at loading under field conditions.

Loading of broilers for transport to the processing plant poses a notable injury risk for broilers. Therefore, the poultry industry has developed mechanical methods as alternatives to manual loading methods. Our objective in the present study was to compare manual loading (MAN) of broilers with the mechanical loading (MECH). We assessed the injuries of broilers of 12 MAN and 12 MECH flocks on-farm before and immediately after loading, documented the numbers of broilers dead on arrival reported by the processing plant, and assessed the circumstances at loading. A smaller number of broilers with a hematoma (≥0.5 cm in diameter) on the wing were observed after MAN compared with MECH using the examined harvester (MAN vs. MECH odds ratio: 0.16; 95% confidence interval: 0.10, 0.28). The number of broilers with severe wing injuries did not differ between the loading methods. The number of broilers dead on arrival was greater in mechanically loaded flocks (MAN vs. MECH odds ratio: 0.26; 95% confidence interval: 0.10, 0.68), but lower than in comparable studies. We observed a lower average stocking rate than targeted in the drawers of MECH containers, most likely because the used harvester can adapt to short-term changes in weight and adjust the stocking rate during the loading process. A longer total loading duration in MAN was associated with an increase of wing hematomas, and the involvement of more working people per 10,000 broilers during MAN was associated with a lower occurrence of hematomas. The total loading duration in MECH had no notable influence on the occurrence of injuries. Physical conditions of the involved personnel might play a larger role in MAN than in MECH. The harvester that was examined should be further developed to reduce the occurrence of hematomas. Our results indicate that the choice of loading method alone does not determine the injury risk, and multiple factors are associated with broiler welfare during loading. It is important that the chosen method is performed under the most adequate conditions.