The final moments of a pig's life at slaughter represent a critical welfare point where failures cause significant conscious suffering. Electrical and CO2 stunning methods each have distinct welfare profiles requiring ongoing improvement.
CO2 stunning causes visible distress in pigs during the period between exposure and unconsciousness, as the gas is aversive at high concentrations. This is a known welfare problem for which better alternatives exist in principle but have not yet been commercialised at scale. Electrical stunning avoids this problem but requires individual handling. Developing and deploying less aversive stunning methods is an urgent welfare priority.