The slaughter of over one billion broiler chickens annually in the UK requires humane stunning systems. Water bath stunning remains common despite welfare concerns, and gas stunning offers improvements.
Broiler slaughter welfare is determined primarily by the stunning system used and the competence with which it is operated. Water bath systems, while widely used, carry inherent risks: birds are inverted and shackled before stunning (causing distress), and inadequate current settings cause painful pre-stun shocks. The contamination of the water bath with faeces also creates food safety concerns. Gas-based CAS systems eliminate shackling before stunning, reduce handling stress, and when using inert gases provide effective unconsciousness without the aversive gas burning of CO2. Consumer and retailer pressure for gas stunning adoption has accelerated the transition in recent years.