The welfare of pigs during slaughter depends on effective stunning and handling, with significant variation in practices across the industry.
Pig welfare at slaughter is a significant concern because both standard stunning methods have welfare limitations. CO2 stunning, while commonly used for its operational advantages including reduced handling and physical restraint, causes a period of acute respiratory distress before pigs lose consciousness. Pigs in CO2 chambers vocalise and attempt to escape, indicating aversive experience. Head-only electrical stunning achieves insensibility rapidly when applied correctly but requires physical restraint that is itself stressful. High-concentration CO2 systems have better welfare outcomes than standard concentrations but remain imperfect. Ongoing research into improved stunning methods including inert gas and nitrogen mixtures is driven by welfare evidence.