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.

Pathological manifestations observed in dead-on-arrival broilers at a Danish abattoir.

1. The mortality of broilers during pre-slaughter handling, including harvesting and transport, is an issue of increasing public concern which has led to the adoption of Council Directive EC/43/2007 implementing abattoir surveillance regarding the number of dead-on-arrival (DOA) broilers. 2. Pathological lesions and causes of death of DOA broilers at a Danish abattoir were investigated in a cross-sectional study comprising 300 DOA broilers (25 broilers from each of 12 randomly selected flocks). Major pathological manifestations of DOA broilers included severe pulmonary congestion (51.5%), lung congestion in combination with trauma (12.5%), trauma (10.2%), nephropathy accompanied by dehydration and/or discolouration (8.8%), morbus cordis (2.0%), septicaemia (1.7%) and suspected septicaemia (1.0%). Lung congestion accompanied by circulatory disturbances in other tissues was suggested to be due to suffocation. 3. Analyses of pathological diagnoses revealed that DOA broilers can be divided into two main categories, lung congestion and trauma, based on the chronicity of the lesions, both of which are primarily related to management and handling procedures. Most DOA broilers examined (74.2%) were estimated to have died as a consequence of events during pre-slaughter handling underlining the importance of increased focus on handling-related factors to reduce DOA rate.

Evaluation of the Danish footpad lesion surveillance in conventional and organic broilers: Misclassification of scoring.

Danish legislation prescribes surveillance of footpad dermatitis (FPD) at slaughter as an indicator of on-farm broiler welfare. The 3-point scale being used was originally developed in Sweden to score feet from conventional broilers, but the extent and causes of misclassifications have not been investigated, neither in conventional nor organic broilers. Hence, we investigated the performance of the official Danish FPD scoring system in conventional and organic broilers by assessing agreement between official scores from the slaughterhouse and consecutive scoring of the same feet by a reference method. We also investigated the impact of performing an incision of the footpad during scoring. In total, 902 conventional and 897 organic broiler feet (∼100 per flock from 18 flocks) were collected at a large Danish slaughterhouse for the official FPD surveillance system. Laboratory scoring, according to predefined criteria for visual and invasive investigations of the feet derived from the official system, was compared to the official scores assigned at slaughter. Footpad lesions were primarily chronic, representing a wide range of severity. Marked differences in color, shape, and degree of papillary hypertrophy and hyperkeratosis of organic and conventional feet were observed. Low agreement primarily regarding score 2 lesions was observed when comparing official and reference foot scores in conventional (0.31) and organic (0.05) broilers. Variation in agreement when comparing flock scores suggested a non-systematic bias, which might be attributed to differences among official raters. The very low agreement in feet from organic broilers shows that these were more difficult to score than conventional. This might be due to a mismatch between lesion characteristics and scoring criteria, or because the lesions were less severe. Strictly visual examination detected 3 out of 4 score 2 lesions identified by the reference method. This study indicated that a large proportion of severe FPD lesions go unnoticed in the official Danish scoring system. The results further suggested that the complexity and impracticality of the scoring criteria impede uniform scoring among raters and production systems.