The method used to stun poultry before slaughter has major welfare implications for the hundreds of millions of birds processed annually in commercial facilities.
Poultry slaughter welfare represents a massive-scale welfare issue concentrated at a single technological intervention point. The live-shackle water bath system still used for most commercial poultry involves conscious birds being hung by their legs, inverted, and moved along a line before stunning - a process that causes significant distress from inversion and handling before any welfare benefit of stunning is applied. Pre-stun shocks from contact with water before proper head positioning add an additional pain event. Controlled atmosphere systems stun birds in their transport containers, avoiding the distress of live shackling entirely. The transition from water bath to controlled atmosphere stunning represents one of the highest welfare-impact changes available in poultry processing.