Stunning failure at slaughter - where animals regain consciousness before or during killing - is a significant but underreported welfare failure requiring improved monitoring and technical standards.
Stunning failure causes the most severe welfare outcomes at slaughter - an animal regaining consciousness while being killed experiences acute pain and fear. The welfare imperative for effective stunning is therefore absolute. Stunning failure arises from equipment malfunction, inadequate maintenance, poor operator training, and incorrect application. Monitoring post-stunning indicators - absence of rhythmic breathing, absence of eye blinking, relaxation of the jaw and limbs - is required but inconsistently practiced. Mandatory CCTV has improved oversight but cannot substitute for trained official veterinarians actively monitoring stunning effectiveness. Higher animal throughput speeds increase stunning failure risk.