Behavioral Responses of Broilers to Different Gaseous Atmospheres

Abstract

This study was conducted to determine the differences in behavioral response of broilers when they come into contact for the first time with gas mixtures that can be used for stunning.

The six test groups were divided into four experimental groups that were exposed to gas mixtures used for stunning and two control groups that were exposed to atmospheric air. The different gas mixtures and their concentrations were a) air, no flow (control−); b) circulating air, flowing (control+); c) >90% Ar in air; d) 60% CO₂ in air; e) 40% CO₂ and 30% O₂ in air; and f) 70% Ar and 30% CO₂ in air. The behavior of the broilers before entering the gas tunnel, the number of birds that moved into the gas mixture, and the behavior in the gas mixture were recorded on video and analyzed afterward.

No differences among the groups were observed in the number of broilers that walked into the gas tunnel or in the number of birds that tried to return to the cage. Exposure of broilers to the 70% Ar and 30% CO₂ mixture resulted in the fastest loss of posture. The number of broilers exhibiting headshaking and gasping was least in the >90% Ar in air mixture. Convulsions were rarely seen in the 40% CO₂ and 30% O₂ mixture; the other gas mixtures resulted in severe convulsions.

The experiment did not indicate that broilers could detect or avoid increased CO₂ or decreased O₂ levels when they come into contact with such atmospheres for the first time.

behavior, broilers, argon, carbon dioxide, gas stunning

Author notes

1

To whom correspondence should be address: M. A. Gerritzen, Institute for Animal Science and Health (ID-DLO), PO Box 65, 8200 AB Lelystad, The Netherlands; e-mail: .