Addition of anaesthetics to feed or water

An anaesthetic agent (e.g. alpha-chloralose) can be mixed with poultry feed or water in order to kill birds in houses. The birds which are not killed directly but are only anaesthetised must be killed immediately by another method such as cervical dislocation. In order for this method to be successful the birds must consume sufficient quantities of anaesthetic rapidly. In order to encourage birds to eat or drink the anaesthetic it may be worthwhile to fast them for a period of time.

Considerations when using anaesthetics during depopulation due to disease control

Using anaesthetics to kill birds is advantageous in that it requires relatively low levels of human labour. As the agents are added to the feed and water the birds can be left to consume it themselves. Additionally, handling of birds is not required until they are anaesthetised, which make handling easier while reducing distress for the birds. As the skin remains unbroken and carcase intact, there should be no release of contaminated body fluids entering the environment ensuring the disease transmission risk is kept to a minimum.

There are a number of disadvantages associated with this method. The dose required to kill a house of birds may be difficult to calculate and there is no guarantee the animals will ingest the drugs as alterations to taste may cause the animals to reject the feed and water. For this reason, variable results may be obtained. Targeting of specific animals is not possible and, outside of a controlled environment, non-target animals may accidently access the medicated feed or water. The time taken for animals to consume the food and be affected may vary considerably throughout a shed. It is also possible that animals which are already anaesthetised or dead may prevent other individuals from accessing the feed and water points. Care is essential in the preparation and provision of treated feed or water and in the disposal of untreated treated feed/water and contaminated carcasses.

Conclusion – species and situations

This method is suitable for killing large numbers of poultry in houses. However, due to welfare concerns this should only be used as a last resort. 

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