How controlled atmosphere stunning provides better welfare outcomes than conventional water bath stunning for commercial poultry.
Controlled atmosphere stunning represents the most significant available improvement in commercial poultry slaughter welfare. By rendering birds insensible before they are handled, shackled, or enter the slaughter process, CAS eliminates the most severe welfare problems of conventional water bath stunning: pre-stun electrical shocks, conscious shackling, and the distress of handling during the slaughter process. Not all CAS is equal — CO2 systems cause measurable aversive responses before unconsciousness, while low-oxygen inert gas systems produce the most peaceful induction. Consumer pressure on retailers for CAS commitments has been effective in the UK market and provides a model for driving welfare-based supply chain requirements elsewhere.