Welfare assessment of conventional and organic broilers in Denmark, with emphasis on leg health

The aim of this study was to survey and report the walking ability in broilers housed in both conventional and organic production systems in Denmark. To this end, the authors assessed the walking ability, by using the Bristol scale, in 31 conventional broiler flocks and in 29 organic broiler flocks distributed across Denmark. In addition, assessment of contact dermatitis, leg abnormalities, scratches and plumage cleanliness, as well as postmortem analysis of tibial dyschondroplasia, was performed in conventional broilers. The survey found a prevalence of 77.4 per cent of impaired walking ability (gait score (GS) >0) in conventional broilers and 38.1 per cent in organic broilers. The prevalence of severe lameness (GS >2) was 5.5 per cent and 2.5 per cent for conventional and organic broilers, respectively. The prevalence of tibial dyschondroplasia in conventional broilers was 4.7 per cent. The results on other welfare indicators are also presented for conventional broilers. The results from the present and previous surveys indicate that the prevalence of impaired walking ability in broiler chickens in the Danish conventional production system is high, but the severity has been steadily decreasing over the last 19 years. Furthermore, the results from the survey of organic broilers suggest that lameness is less prevalent and severe in this system relative to conventional production.