Slaughter welfare for pigs depends critically on effective stunning that ensures unconsciousness before slaughter, with CO2 stunning raising significant welfare concerns.
Pig slaughter welfare remains a significant unresolved welfare issue despite decades of scientific evidence about the aversion and distress caused by CO2 stunning. The CO2 gondola system is used for the vast majority of commercial pig slaughter globally due to its efficiency and automation advantages. However, the welfare evidence is clear: pigs entering high CO2 atmospheres show unambiguous signs of severe distress including rearing, head shaking, and apparent panic for 20-30 seconds before losing consciousness. Low-oxygen alternatives produce unconsciousness without this distress period and represent a welfare improvement that industry has been slow to adopt. Consumer and regulatory pressure can accelerate transition.