Controlled atmosphere stunning using inert gas or low oxygen mixtures offers welfare advantages over electrical water bath stunning for poultry, but involves welfare trade-offs that require careful evaluation.
Slaughter method is one of the most significant welfare determinants for poultry. Electrical water bath stunning, widely used, requires hens to be shackled upside down while conscious — an inherently frightening position — and exposed to electrical current. Controlled atmosphere stunning avoids shackling stress but CO2 at the concentrations typically used causes aversive breathlessness before unconsciousness. High-concentration inert gas (argon or nitrogen) provides unconsciousness without aversion and represents the current best-practice option. Transitioning the industry to these methods represents a meaningful and achievable welfare improvement.