Pig Slaughter Welfare: Stunning Methods and Best Practice

Slaughter welfare for pigs depends critically on effective stunning before killing, with carbon dioxide systems raising significant welfare concerns.

Key Facts

Carbon dioxide stunning involves pigs inhaling high concentrations of CO2 gas, which is aversive and causes distress.
CO2 is the most widely used stunning method in large-scale pig slaughter due to group handling efficiency.
High CO2 concentrations cause breath-holding, vocalisation, and visible distress before unconsciousness.
Electrical stunning can achieve effective unconsciousness rapidly but requires correct application of parameters.
Controlled atmosphere stunning using inert gas mixtures including argon provides less aversive unconsciousness.
Stunning effectiveness monitoring is required by EU regulations but compliance and audit quality varies.
Ritual slaughter without prior stunning occurs in some EU countries under religious exemptions.
Post-stunning intervals must be minimised; regaining consciousness before bleeding is a serious welfare failure.

Welfare Considerations

Pig slaughter welfare is one of the most significant and contested welfare issues in food animal production. Carbon dioxide stunning, used for the majority of pigs slaughtered globally, causes a documented period of aversion and distress before unconsciousness. The industry defends it on operational efficiency grounds, but welfare scientists consistently document its aversive qualities and advocate for less aversive gas alternatives. Consumer and retailer awareness of stunning method differences is low, preventing effective market pressure for improvement. The welfare case for transition from CO2 to inert gas or electrical stunning for pigs is scientifically sound and should be pursued through both regulatory and consumer market channels.

What You Can Do

Support campaigns calling for transition from CO2 to less aversive stunning methods in pig slaughter.
Engage retailers about whether they require specific stunning method standards from pork suppliers.
Advocate for regulatory restriction of CO2 stunning in pig slaughter in favour of less aversive alternatives.
Support organisations monitoring and improving slaughterhouse welfare standards and audit quality.
Follow the science on gas stunning alternatives and share evidence with food system decision makers.