Pig slaughter welfare depends critically on stunning method effectiveness, equipment maintenance, and handling practices in the lairage — with CO2 stunning and electrical stunning each having welfare tradeoffs.
CO2 stunning for pigs involves a period of aversive induction before loss of consciousness — this is not a welfare-neutral stunning method but a tradeoff where unconsciousness is achieved at the cost of seconds of panic and distress during CO2 induction. This welfare cost affects every pig slaughtered through CO2 stunning systems, multiplied across the hundreds of millions of pigs processed through these systems annually. Alternative stunning approaches including inert gas or modified atmosphere stunning can render pigs unconscious without the aversive CO2 induction phase. The technical and economic barriers to adopting improved stunning methods are real but not insurmountable — progress requires regulatory requirements and industry investment. Lairage management that minimizes fighting, heat stress, and handling stress reduces the pre-stunning welfare burden.