Slaughter welfare is the final welfare challenge in a pig's life. The period from lairage to stunning and killing carries significant welfare risks that are under-appreciated relative to on-farm welfare. Improving slaughter welfare is achievable and represents a meaningful intervention for millions of pigs annually.
Pre-Slaughter Stress
Pigs experience significant stress in the pre-slaughter period: transport to an unfamiliar environment, mixing with unfamiliar pigs (causing fighting), lairage conditions, noise, handling in races, and the approach to the stunning point. Pre-slaughter stress elevates cortisol, accelerates glycogen depletion (affecting meat quality through pale, soft, exudative — PSE — meat), and compromises welfare. Minimising these stressors improves both welfare and product quality.
Lairage Management
Rest pigs in lairage for a minimum of 1-3 hours before slaughter to allow recovery from transport stress
Avoid mixing unfamiliar pigs in lairage — fighting causes injuries and acute stress
Adequate water provision — pigs are often dehydrated after transport
Temperature management: pigs are sensitive to heat; lairage should be temperature-controlled, particularly in summer
Minimise noise — pigs are sensitive to high-frequency sounds; sudden noises cause fear responses
Stunning Methods
CO2 stunning (high concentration): Effective for unconsciousness but highly aversive — pigs show strong aversion responses as CO2 concentration rises. Widely used due to throughput efficiency. Research into reduced CO2 or alternative gas mixtures ongoing.
Electrical stunning: Head-only or head-to-back electrical stunning can produce immediate insensibility if parameters are correct. Reliability depends on operator skill and equipment maintenance. CCTV monitoring improves compliance.
Captive bolt + electrical: Captive bolt to head followed by electrical application to the chest provides excellent welfare outcomes if properly executed.
Monitoring & Regulation
WATOK (Welfare at Time of Killing) regulations require official veterinarians and animal welfare officers at slaughterhouses. CCTV installation in all UK slaughterhouses (introduced 2018) has improved welfare monitoring and provided evidence of non-compliance in some cases. Official welfare audits and proactive assurance scheme requirements are driving improvement.