The welfare of pigs at slaughter depends on stunning method, stunning quality, and the management of the lairage period before killing.
Pig slaughter welfare is complicated by the dominance of CO2 stunning - a method that causes measurable aversive responses before loss of consciousness. Research has clearly established that pigs exposed to CO2 at concentrations used for stunning show distress behaviours during the 15-20 seconds before unconsciousness. Alternative inert gas mixtures have shown lower aversive onset. The welfare case for transitioning away from CO2 to less aversive stunning methods is strong.