Slaughter is the final and critically important welfare moment for pigs, and the stunning and killing methods used have profound implications for the suffering experienced by billions of animals annually.
Pig slaughter welfare is one of the highest-impact issues in animal welfare given the enormous number of animals involved. The widespread adoption of CO2 gas stunning in large commercial facilities, driven by operational convenience rather than welfare evidence, exposes billions of pigs annually to a period of significant distress and pain before unconsciousness. Research consistently demonstrates that pigs find CO2 highly aversive — they actively avoid it, vocalise excessively during induction, and show signs of severe distress. Better alternatives exist, including low-oxygen or controlled atmosphere stunning using nitrogen, and these are available at feasible cost. The reluctance of the industry to adopt less aversive methods in the absence of regulatory compulsion represents a significant and ongoing welfare failure.