C38 | Animal-based indicators and animal welfare assessment in broiler chickens: development of a composite indicator for monitoring

T. Ottonello¹, E. Fontanella², S. Golotta², G. Di Giacinto¹, F. Chiesa¹, F. Panebianco¹, T. Civera¹. | ¹Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, Torino; ²Servizi Veterinari area B, ASL CN2, Alba, Italy

Purpose. The aim of the study was to develop and validate a composite indicator (M3) for assessing animal welfare in broiler chickens by analysing Animal-Based Indicators (ABI) recorded by official veterinarians at slaughter. The indicator was designed to provide a standardised and objective tool to support the monitoring of animal welfare throughout the production chain by comparing historical and seasonal results. Methods A total of 20,628 batches, corresponding to 154,775,234 birds, slaughtered between 2016 and 2024 in an industrial poultry plant in north-western Italy were analysed. The ABIs selected and recorded during the post-mortem inspection include: Foot Pad Lesions (FPL): foot lesions related to farm management; Sanitary Discard (SIS): percentage of sanitary discard detected at the slaughterhouse; Dead On Arrival (DOA): mortality on arrival, indicative of transport management. The data were processed by normalisation with respect to moving geometric means (MGM) and historical seasonal cut-offs, calculated for each indicator. The M3 indicator was obtained as the weighted average of the normalised ABIs (FPL 50%, SIS 40%, DOA 10%), limiting the influence of extreme values through winsorisation. The statistical analysis included preliminary verification of data distribution and the presence of seasonal variability. The distribution of the indicators was assessed using the Kolmogorov-Smirnov and Lilliefors tests, while the differences between seasons were investigated using the Kruskal-Wallis test. Results The overall average values of the indicators were 32.2 (FPL), 0.5% (SIS) and 0.4% (DOA). The study shows a progressive reduction over the years in the DOA (average from 0.0045 to 0.0020) and SISm (average from 0.0050 to 0.0030) indicators, while FPL shows an increase up to 39.1 in 2024 (with a peak in 2021). The analysis confirmed a strong seasonal influence on all ABIs, particularly on FPL (Kruskal-Wallis. < 0.001). Conclusions The integrated analysis of FPL, SIS and DOA allows for an objective and retrospective assessment of animal welfare in broiler chickens. The FPL trend provides information on farm production performance, while SIS and DOA allow monitoring of the incidence of lesions detected at post-mortem examination and transport mortality, respectively. The ability to compare results through historical curves and annual rankings allows data to be interpreted in the context of temporal variability and differences between operators. The M3 composite indicator, constructed as a weighted average of the three main variables, is a synthetic tool for the continuous monitoring of animal welfare. The model supports official veterinarians in their control activities and food business operators in managing conditions along the supply chain, facilitating the identification of persistent management anomalies compared to normal seasonal variations.