Methods of analgesia and euthanasia in backyard poultry

Abstract

The keeping of chickens in the backyard is growing in popularity in urban and suburban areas, numbers of animals are increasing and as a result small animal practitioners are more and more frequently faced with chickens as patient. Clinical conditions in backyard poultry often require the treatment of pain. The challenges regarding the adequate use of analgesics include: 1. Recognition and assessment of pain, which necessitates good knowledge of chicken behaviour, 2. Selection of the adequate drug and dosage based on evidence that is often not available for chickens, but spread over different species of birds, and 3. Implementation of food safety regulations, which result from the dual use of backyard poultry as «food producing pets». Analgesics used in chickens include opiates, nonsteroidal anti-inflammatory drugs and local analgesics. The opiate butorphanol has been shown to have an analgesic effect of approximately two hours in chickens. Tramadol and methadone show some promise as analgesics, but more evidence is needed especially regarding bioavailability. The nonsteroidal anti-inflammatory drugs meloxicam and carprofen appear to have an analgesic effect. Variable metabolism between breeds of chickens and the risk of accumulation, especially when used for periods exceeding five consecutive days, need to be taken into account regarding dosage. Lidocaine and bupivacaine have successfully been used in chickens for nerve blocks and spinal anaesthesia and should be included as part of multimodal analgesia especially during surgery. In cases, where termination of life is necessary the preferred method consists of an injectable anaesthesia followed by intravenous application of a barbiturate.