Sulima K1, Hunter DB1, Dam A2, Hill J3, Chiappetta ME1, Turner PV1Department of Pathobiology, Ontario Veterinary College, University of Guelph1Ontario Ministry of Agriculture, Food and Rural Affairs2Alberta Agriculture and Rural Development3
Determining humane, efficient, safe, and economically viable methods for depopulation of commercial poultry flocks is an important emerging issue. Various methods have been proposed to deal with mass depopulation of poultry for foreign animal disease outbreaks and for on-farm depopulation of spent laying hens. The Alberta Modified Atmosphere Chamber (AB-MAC) is a portable unit holding up to 650 birds that uses carbon dioxide (CO2) to create hypercapnia, a condition leading rapidly to unconsciousness, cardiac arrhythmias, and brain death. The objectives of this study were to evaluate chamber operation, animal well-being, and personnel safety during use of AB-MAC for spent hen depopulation in a controlled field setting. Candidate gasses including CO2, argon/CO2 and nitrogen/CO2 gas combinations were first evaluated by pumping them into the empty AB-MAC at consistent flow rates. CO2 and O2 concentrations were measured at various heights within the chamber to determine if any of these gasses or mixtures would result in appropriate CO2 and O2 levels leading in rapid unconsciousness and death, as determined from previous studies. Only 100% CO2 was found to be suitable with this chamber. During in vivo studies, hens surgically instrumented for telemetry were lowered into the gas-primed chamber, and time to unconsciousness, onset of cardiac arrhythmias, and brain death were recorded. Results from these trials indicate that the chamber can be used to rapidly stun and kill hens; however, current field loading rates likely exceed the time required for initial stunning, particularly at the middle and top of the chamber. These findings will be used to provide regulatory authorities and industry with recommendations for routine use of the AB-MAC.