Comparison of flock characteristics, journey duration and pathology between flocks with a normal and a high percentage of broilers 'dead-on-arrival' at abattoirs.

This study investigated high mortality in broilers transported to slaughter in Norway by comparing data from flocks with normal and high mortality during transportation. The data sources consisted of necropsy findings in 535 broilers dead-on-arrival (DOA), production data and slaughterhouse data, along with average journey duration for the 61 associated flocks. The mean Norwegian DOA% for 2015 was 0.10. In this study, normal-mortality flocks were defined as flocks with a mean DOA% up to 0.30 and high mortality as flocks with a mean DOA% above 0.30. DOA% was calculated per flock. The most frequent pathological finding was lung congestion which was observed in 75.5% of the DOA broilers. This postmortem finding was significantly more common in broilers from high-mortality flocks (89.3%) than in DOA broilers from normal-mortality flocks (58%). The following variables had a significantly (P<0.05) higher median in the high-mortality flocks: flock size, 1st week mortality, foot pad lesion score, carcass rejection numbers and journey duration. The results indicate that high broiler mortality during transportation to the abattoir may be linked to several steps in the broiler production chain. The results suggest that preventive measures are to be considered in improvement of health and environmental factors during the production period and throughout the journey duration.