Inter-rater agreement in visual assessment of footpad dermatitis in Danish broiler chickens

1. The performance of the scoring in the Danish footpad dermatitis (FPD) surveillance system was evaluated by determining inter-rater agreement in visual inspection of FPD in broilers between two independent raters (R1 and R2) and the official scoring at a Danish slaughterhouse. 2. FPD scores were evaluated in 1599 chicken feet. The two raters and the slaughterhouse scored equal proportions of score 0. So did R1 and R2 when assessing score 1 and the more severe lesion score 2, whereas the slaughterhouse scored a markedly higher proportion of score 1 and a lower proportion of score 2. Aggregated FPD flock scores ranged from 5 to 163 (R1 and R2) and from 8 to 107 (slaughterhouse). 3. The level of agreement between the two raters was high for scores 0, 1 and 2 and for flock scores. Agreement between raters and the slaughterhouse was lower when R1 and R2 recorded score 2 than when they recorded scores 0 and 1. 4. This study indicates that the occurrence and severity of lesions are underestimated in the official Danish FPD scoring system.