How poultry are rendered insensible before slaughter has major welfare implications for billions of birds. Comparing stunning methods reveals significant welfare differences.
The slaughter of 70 billion chickens annually involves billions of individual welfare moments that are largely invisible to consumers. Conventional water bath stunning requires live birds to be shackled upside down by their legs - a stress-inducing position - before electrical stunning that is itself imperfect. A significant percentage of birds in water bath systems may receive inadequate stunning and regain consciousness before slaughter. Controlled atmosphere killing, which renders birds unconscious before any physical handling, represents a significant welfare improvement but requires capital investment. The gap between current standard practice and achievable best practice in poultry slaughter represents one of the largest tractable welfare improvements available in animal agriculture.