Pig Welfare at Slaughter: Stunning Effectiveness and Line Speed Management

Pig slaughter involves multiple welfare-critical stages. Stunning effectiveness and line speed management determine whether millions of pigs each year die humanely or suffer preventable pain and fear.

Key Facts

Approximately 1.3 billion pigs are slaughtered globally each year; the EU alone processes around 250 million annually
Electrical head-only stunning is the most common pig stunning method but requires precise electrode placement and adequate current
CO2 stunning renders pigs insensible before shackling but causes a distressing aversive phase as pigs inhale high-concentration CO2
High-concentration CO2 causes breathlessness and panic; pigs exposed to it show vigorous avoidance and vocalise strongly before losing consciousness
Inert gas stunning (argon or nitrogen) avoids the aversive CO2 experience and is considered a higher-welfare alternative
Line speed pressure creates risk of stun failures and inadequate time between stunning and bleeding
CCTV in stunning areas, now mandatory in EU slaughterhouses, has improved accountability and compliance rates

Welfare Considerations

Pig slaughter welfare is determined primarily by stunning method and execution quality. Electrical head-only stunning, improperly applied, causes painful but sublethal electrical shocks before effective stun. CO2 stunning avoids this risk but replaces it with a different welfare problem: the aversive period before loss of consciousness during which pigs experience breathlessness and distress. High-concentration CO2 is universally aversive in pigs; research consistently documents strong escape attempts and vocalisation. Inert gas alternatives produce insensibility without this aversive phase. Line speed is a systemic risk: pressure to maintain throughput compromises the care and time required for effective stunning and post-stun monitoring. CCTV and independent audit have improved but not eliminated these failures.

What You Can Do

Support campaigns by Compassion in World Farming and Humane Society International for mandatory inert gas stunning replacement of CO2
Ask pork retailers about the stunning methods used at their supplier slaughter plants
Advocate for independent welfare auditing with published results at all licensed pig slaughter plants
Support mandatory CCTV in all UK and EU slaughter areas with regulator access to footage
Reduce pork consumption or choose certified high-welfare products from supply chains with audited slaughter standards