Broiler stunning in electrical water bath: Validation of an animal welfare-based method for assessing stunning...

Electrical water bath stunning remains the predominant method for poultry slaughter in Europe, yet its welfare implications are still debated. This study assessed the current status of stunning effectiveness in broiler chickens under commercial conditions, providing a foundation for future comparisons with controlled atmosphere stunning. Behavioral observations were made in 1 slaughterhouse over 2 study years (2021 and 2022) and were analyzed separately for each year across broilers from 4 fattening methods (LIT: light conventional fattening method, HEV: heavy conventional fattening method, LBL: label fattening method, ORG: organic fattening method). The analysis aimed to explore whether stunning performance differs according to fattening method, animal age, transport duration, carcass weight, weather conditions, and total electrical current in the electrical water bath. Stunning effectiveness was evaluated in 3 phases: pre-stunning (shackling), during stunning, and post-stunning. In each phase, key behavioral indicators, such as signs of inadequate stunning (e.g., wing flapping, body movements, rhythmic breathing), were systematically recorded. The results showed that pre-stunning behavior varied among fattening methods in 2022 (defensive reactions: ORG [0.82%] vs. LBL [0.05%]; wing flapping: LIT [29.00%] vs. OGR [17.00%], HEV [21.00%], and LBL [12.60%]), with older and lighter animals showing more pronounced defensive or flapping responses. After stunning in 2021, only ORG broilers showed cases of inadequate stunning (0.01%), whereas no incidences were observed in LIT (0.00%) and HEV broilers (0.00%). These findings highlight that even minor differences in handling and animal characteristics can significantly affect stunning effectiveness and animal welfare.