Broiler Chicken Stunning Methods During Slaughter

Stunning is the process of rendering broilers unconscious or insensible before slaughter and various mechanisms may be used in facilities to achieve insensibility (Humane Slaughter Association, 2015). The methods used depend on the facility's location (on-farm vs. in a slaughter plant), the number of broilers slaughtered, and company program-specific criteria and restrictions. The Humane Slaughter Act of 1978 was passed in the United States to protect livestock handling during slaughter. However, it does not address the slaughter of poultry. Instead, the U.S. requires that poultry slaughter establishments follow “good commercial practices”. Further, regulations require that good commercial practices must ensure a thorough bleeding of the poultry carcass and that breathing has stopped before scalding. As a result, stunning is common practice for broiler chicken processing in the U.S. (USDA-FSIS, 2015). This is a different regulatory system than the European Union, which has a specific legislation that requires broilers to be insensible to pain until death occurs (Official Journal of the European Union, 2009).

Stunning is used to render birds insensible to the pain caused during the slaughter process. Stunning prevents unnecessary pain and prolonged distress (Bracke et al., 2020) during the processing phase. Not achieving insensibility is a major welfare concern, due to the pain and distress broilers would face during the cutting and bleed-out phases.

The stunning of broilers before slaughter helps ensure that broiler welfare is protected. In addition, stunning renders broilers unconscious to permit enough time for the bleeding phase (i.e., cutting of the ventral arteries) to occur (Bracke et al., 2020). Without stunning, unnecessary pain and distress would be experienced by broilers, leading to animal welfare concerns. Each stunning method has advantages and disadvantages in terms of in terms of economic (labor) and animal welfare considerations (pain, distress, success rate). The chosen method must demonstrate successful stunning while being feasible for the producer.