In case of an epidemic situation killing of poultry flocks can be prescribed in order to reduce the spread of disease. According to the German law on Animal Welfare animals shall only be killed after stunning in order to avoid pain and suffering.
In accordance with the Council Regulation (EC) No. 1099/2009 and the German law on the protection of animals during slaughter and killing, stunning with carbon dioxide is permitted. Animals perceive carbon dioxide with increasing concentrations as aversive until they lose consciousness and sensibility. The time of gas influx plays an important role: The time to loss of consciousness and sensibility is shortened if the animals are directly exposed to high concentrations of carbon dioxide (rapid influx). However, this period of time will be lengthened during a progressive exposure to gas (slow influx) but gas concentrations with strong irritant effects are only reached when the animals are already unconscious.
Therefore, different flows of carbon dioxide are systematically investigated. The specific examination of such time-concentration-curves during gas stunning of poultry shall help to answer the question if a slow influx of carbon dioxide induces unconsciousness sufficiently fast without causing pain and suffering. Furthermore, an “ideal” gas flow can possibly be determined to minimize stress.