The method used to render chickens unconscious before slaughter has major welfare implications affecting hundreds of millions of birds every year.
Slaughter method is among the highest-impact welfare interventions available for broiler chickens given the scale involved. Live-shackle electrical stunning, where conscious birds are hung upside down and passed through an electrified water bath, causes pain and distress before unconsciousness. Controlled atmosphere systems — using high-concentration CO2 or inert gases — render birds unconscious before any human handling, eliminating the shackling trauma. The welfare improvement at scale from transitioning the industry would be enormous.