McDonald’s Controlled Atmosphere Stunning Report

A report by the McDonalds Corporation on Controlled Atmospheric Stunning (CAS) and electrical stunning concludes that CAS does not offer “significant advantages” over the electrical systems already in use by U.S. suppliers, and that McDonald’s will support usage of both CAS and electrical stunning.

McDonald’s global animal welfare standards require that “animals be rendered insensible (so as not to experience pain) prior to and during the slaughter process.” In a 2005 report, the company concluded that “CAS has potential” but that, “given the remaining unanswered questions, it would be premature to require the adoption of what is still an emerging technology.” McDonalds said it would “monitor” research on CAS and other stunning methods, with this being the most recent update.

Currently, most poultry slaughterhouses render birds “insensible” through either electrical or controlled atmosphere stunning. Electrical stunning systems have many problems with respect to unloading and transferring processes, as well as the potential for birds to receive a “pre-stun shock.” Under CAS, birds are moved into compartments that contain the gas or gases, resulting in loss of consciousness, followed by brain death.

This review of the scientific literature indicates that there is no consensus on which approach is preferable for stunning. In 2007, McDonald’s conducted its own comparative analysis between the two systems; the final results did not show that either CAS or the combined CAS/low voltage electrical stunning system offers significant advantages over the low voltage electrical system already in use. The company will continue to use the current electrical stunning systems in place.

It is important to note that the McDonalds review is from the perspective of productivity and meat quantity and quality. The sole measure of animal welfare was “distress,” as evaluated by the presence of broken or bruised wings and limbs. This limited view of animal welfare dismisses psychological distress and myriad other physical issues resulting from overcrowding and improper stunning of chickens.