Pig slaughter welfare depends critically on pre-slaughter handling, stunning method and efficacy, with significant variation in practice and outcomes across the tens of thousands of pigs slaughtered daily in the UK.
Pig slaughter welfare is compromised by the widespread use of carbon dioxide stunning at high concentrations, which causes pigs to experience panic and aversion responses before losing consciousness. Research has consistently shown that pigs react strongly to CO2, attempting to escape and vocalising. Alternative gas mixtures including argon and nitrogen cause unconsciousness with less aversion. The switch to more humane stunning methods is technologically feasible but requires capital investment that industry is reluctant to make without regulatory requirements. Mandatory CCTV in abattoirs, introduced in England in 2018, provides monitoring evidence but does not itself prevent poor welfare unless acted upon by official veterinarians.