Pig Slaughter Welfare Science 2025: Stunning and Killing Methods

Key Facts

• Carbon dioxide (CO2) stunning is the dominant commercial method globally but causes aversive hypercapnia before unconsciousness
• Research confirms CO2 at concentrations below 80% causes significant distress for 20-30 seconds before stunning
• Controlled atmosphere stunning using inert gases (argon, nitrogen) eliminates the hypercapnia aversiveness
• Head-only electrical stunning is effective but requires immediate slaughter before recovery
• The 2025 EFSA opinion strongly recommends transitioning away from CO2 as the primary stunning method in pigs

Welfare Considerations

Pig slaughter welfare is one of the most significant unaddressed welfare problems in food production. The scale of pig slaughter — billions globally per year — means the welfare impact of suboptimal stunning is enormous. CO2 stunning, despite its dominance, causes measurable aversive experiences before loss of consciousness. Inert gas alternatives eliminate this aversiveness and are technically feasible in modern slaughter plants. The 2025 EFSA opinion provides the scientific basis for regulatory transition, but industry resistance and cost concerns continue to delay adoption. Consumer awareness and retailer commitments are the primary drivers of change in the near term.

What You Can Do

• Support food retailers with explicit commitments to sourcing pork from operations using inert gas stunning
• Advocate for EU and UK regulatory action implementing the 2025 EFSA opinion on CO2 stunning alternatives
• Share pig slaughter welfare evidence with consumers to drive informed purchasing decisions
• Support animal welfare organizations monitoring and reporting on pig slaughter practice globally
• Choose pork with higher welfare certifications that specify slaughter method requirements where available