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Behavioural responses of broiler chickens during low atmospheric pressure stunning
•The welfare of poultry at slaughter is an important issue affecting a large number of animals.•Low atmospheric pressure stunning (LAPS) is a novel approach utilising hypobaric hypoxia.•We examined behavioural responses to LAPS in individuals and groups of broiler chickens.•Birds exhibited a consist...
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| Published in: | Applied animal behaviour science 2016-01, Vol.174, p.90-98 |
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| Main Authors: | , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | •The welfare of poultry at slaughter is an important issue affecting a large number of animals.•Low atmospheric pressure stunning (LAPS) is a novel approach utilising hypobaric hypoxia.•We examined behavioural responses to LAPS in individuals and groups of broiler chickens.•Birds exhibited a consistent series of behavioural responses to LAPS.•These behavioural responses were similar to those seen during hypoxia induced with inert gas.
Low atmospheric pressure stunning (LAPS) is a new irreversible stunning method for broiler chickens (Gallus gallus domesticus), which has the potential to improve welfare during routine slaughter. During LAPS, birds are placed in a hypobaric chamber that allows oxygen to be gradually removed from the environment by the controlled removal of air; the staged process takes 280s and reaches final decompression pressure that is 80.6kPa below atmospheric pressure (nominally 101.3kPa for an absolute vacuum pressure of 20.7kPa). In this study, the behaviour of broilers (50 individuals and 50 focal birds killed in groups of 20) was observed during LAPS. Latencies, total durations, single bout durations and number of bouts were recorded for all behaviours. Three different decompression curves were applied during the process (based on automatically applied settings related to ambient temperature) and their effects on behaviour were investigated. Not all birds displayed all behaviours, but a subset of behaviours (ataxia, loss of posture, clonic and tonic convulsions and leg paddling) occurred in a consistent sequence. In individuals, mandibulation, headshaking and open bill breathing occurred earliest at 44.5±31.6s, 50.8±38.3s and 57.4±35.8s, respectively, after LAPS began. Ataxia was observed on average at 57.3±11.5s, with birds killed at colder temperatures taking slightly longer to succumb to ataxia than those at warmer temperatures. Loss of posture (LOP) is regarded as a behavioural marker for loss of consciousness and it occurred on average at 80.7±17.7s. Clonic and tonic convulsions were displayed after LOP at 110.5±37.6s and 117.4±28.8s after LAPS onset, respectively. Mean time to motionless was 199.4±21.3s. The group data were largely similar to that of individuals but were less reliable due to focal birds being obscured by neighbours. Based on LOP, the data suggest that birds are in a conscious state for longer during LAPS than in controlled atmosphere stunning with inert gases, but although the induction to unconsciousness is m |
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| ISSN: | 0168-1591 1872-9045 |
| DOI: | 10.1016/j.applanim.2015.11.001 |