Slaughter is the final welfare event in a broiler chicken's life. The methods used at this stage — catching, transport, stunning, and killing — determine whether birds experience unnecessary suffering at the end of their lives.
Broiler chicken slaughter involves a sequence of potentially welfare-compromising events: catching, crating, transport, lairage, shackling, stunning, and killing. Each stage carries welfare risks that can be managed through better practice. Catching stress — particularly when performed roughly at night — causes acute fear, wing fractures, and bruising. Transport in crates causes temperature stress, crowding, and deprivation of feed and water for extended periods. Traditional water bath electrical stunning requires conscious birds to be shackled upside-down, causing pain and distress before the stun — a welfare failure that controlled atmosphere systems avoid by stunning birds before shackling. Stun failures in electrical systems result in birds entering the killing phase while conscious — a catastrophic welfare outcome occurring at the scale of millions of birds annually in some estimates. Controlled atmosphere killing with inert gas or high-concentration CO2 stunned birds before handling is increasingly recommended as the most welfare-positive system available at commercial scale.