Poultry slaughter involves billions of birds annually and the welfare of stunning and killing methods has significant implications for conscious experience at the moment of death.
Water bath electrical stunning immobilizes rather than reliably anesthetizes all birds, meaning some percentage experience the full slaughter process while conscious. The shackling process — hanging live birds upside down by their legs on a moving line — causes pain from joint stress and wing flapping injuries that precede even the stunning attempt. Controlled atmosphere stunning, which renders birds unconscious before any handling or shackling, eliminates these welfare problems but requires capital investment that many facilities have not made. The scale of the problem — billions of birds — makes even small percentage improvements enormously impactful.