EUTHANASIA OF POULTRY (Pigeons)
Considerations for Producers, Transporters, and Veterinarians
Euthanasia is a humane death that occurs with a minimum of pain, fear, and distress
In any poultry production system, it is inevitable that some birds will become ill, debilitated, or injured. If the bird is unlikely to respond favorably to treatment, or if treatment is not feasible because of economic or public health considerations, euthanasia may be the best option to prevent the bird from suffering. In addition, healthy spent hens may be killed on-farm for subsequent rendering because their low market value makes it impractical to send them to a processing facility. This pamphlet is designed to aid producers, transporters, and veterinarians in making appropriate decisions regarding euthanasia and on-farm killing of poultry.
Questions to be considered in deciding whether a sick, debilitated or injured bird should be euthanized include:
• Is the bird experiencing pain or distress?
• Is recovery likely?
• Is the bird likely to transmit disease to other birds?
• Is the bird able to access the feed and water?
• Can the bird be treated?
• Is the bird or its eggs suitable for human consumption, or will they be suitable for consumption after recovery or treatment?
General economic considerations may also play a role in deciding whether or not to euthanize a bird.
Considerations for Euthanasia Methods
• Poultry Welfare: The method chosen should minimize the pain and distress experienced by the bird. However, the choice of techniques may be limited in certain environments. In all cases, proper restraint can help to decrease the bird's fear and distress. When possible, poultry should be held gently in an upright position with their wings closed to prevent flapping, not carried upside down by the legs. Covering the eyes with a hand or a piece of cloth exerts a calming effect, as does holding the bird in contact with the handler's body.
• Human Safety: The method chosen should not pose undue risks to the individual performing the euthanasia. Some methods are more dangerous than others, and should only be used under controlled conditions with proper equipment or protection.
• Skill:Appropriate training of personnel is important to ensure that poultry are euthanized appropriately. Untrained personnel in an emergency situation can use some methods, while others, like cervical dislocation, require skill and training to carry out correctly.
• Aesthetics: Some methods may be objectionable to the person performing the procedure because of blood loss or involuntary reflex movements by the bird. Personnel that may euthanize birds should be trained to understand how birds respond to particular euthanasia methods.
• Cost: Some methods are more costly than others are. Some have initial costs associated with the purchase of equipment, but are thereafter inexpensive.
• Limitations: Some methods may be suitable for only certain ages or types of poultry. In addition, some methods involve administration of controlled drugs by a veterinarian.
Table 1: Euthanasia Methods for Poultry
||Human Safety Risk
||Acceptable if carried out by trained personnel
||Low; labor cost
||Acceptable technique for young or small birds, but physically difficult to carry out properly with larger poultry like turkeys and ratites and adult waterfowl, or when large numbers of birds must be killed
||Moderate to high; cost of chamber and gas supply
||Appropriate concentrations must be maintained (see below)
||May be acceptable, but depends on type and age of bird; CO2 is aversive
||Low if used in an enclosed container or area
||Wing-flapping and other terminal movements; gasping
||Moderate to high; cost of chamber and gas supply
||Not acceptable for waterfowl; for other birds, proper levels must be maintained (see below)
||Terminal movements possible
||Moderate; cost of chamber and gas supply
||Not acceptable for waterfowl
||Acceptable if directed to head
||Moderate to high
||Some blood and motion
||Low to moderate; purchase of gun and bullets; safe storage
||Can be used in an emergency to kill larger birds
||Acceptable if carried out by trained personnel
||Some blood; wing-flapping; ratites kick
||Low; purchase of captive bolt
||Can be used for larger birds, particularly ratites and waterfowl; placement of bolt important
||Good providing sufficient current passes through brain and heart to kill bird instantly
||Low to moderate, depending on method
||Muscle contraction due to electricity
||Purchase of equipment
|Only marginally acceptable unless bird is stunned first
||Poor; very bloody
||None, unless stunning equipment is purchased
||None; should only be used in emergencies where other methods are unavailable
||Good if specialized device is used
||Low if equipment used properly
||Unpleasant; some blood and tissue
||Purchase of purpose-designed macerator
||Appropriate for small chicks
||Applicable agents available only to licensed veterinarians; some poultry (like broilers) may need higher doses; carcass disposal
Details of Table 1
• Cervical Dislocation: If carried out near the head area, dislocation of the neck vertebrae from the cranium damages the lower brain region, causing rapid unconsciousness. In order to be humane, dislocation must cause severance of the brain from the spinal cord and carotid arteries. This is best achieved using a stretching motion rather than by crushing the vertebrae. Training of personnel is critical. Small birds can be dislocated by applying a rotational movement to the neck. Adult poultry should be held by the shanks with one hand, and the head grasped immediately behind the skull with the other hand. The neck is then extended and dislocated using a sharp downward and backward thrust. The necks of larger or heavily muscled birds like broiler breeders, turkeys, geese, ratites, and waterfowl are extremely difficult to dislocate. It is therefore recommended that other methods like captive bolt or gas euthanasia be used for birds weighing more than 6.5 pounds. Flapping and other body movements may persist for several minutes after cervical dislocation, although if the vertebrae have been properly dislocated these are reflex reactions. Securing the bird's wings prior to performing the dislocation can prevent involuntary flapping. To ensure death, the bird's throat should be cut after cervical dislocation. If large numbers of birds are to be euthanized cervical dislocation is not an appropriate method because personnel performing the procedure rapidly become fatigued due to the physical effort required.
• Argon: Argon gas is an acceptable method for killing all poultry species except waterfowl, and is not an irritant like CO2. Exposure to argon causes hypoxia. A concentration of 90% argon in air, or a mixture of argon and CO2 (see below), should be used to for euthanasia of newly hatched fowl chicks, ratites, and poults. Older birds should be euthanized using argon with less than 2% residual oxygen.
• Carbon Dioxide (CO2 ): Carbon dioxide causes rapid onset of anesthesia with subsequent death due to respiratory arrest. Death occurs in 2-5 minutes depending on the species and concentration of CO2 used. Poultry can be euthanized using carbon dioxide gas by being placed in containers that are sufficiently airtight to maintain CO2 at desired level. Depending on how many birds are being euthanized, a circulation system may be necessary to ensure that the gas does not become stratified. Birds should be added to the chamber gradually so that proper CO2 levels are maintained. CO2 should always be delivered from vapor delivery cylinders or, if from a liquid delivery cylinder, vaporized first to prevent it from turning into dry ice. To meet the criteria for humane euthanasia, birds already in the chamber must be unconscious before being overlain by other birds loaded after them, and unconsciousness must be maintained until death occurs.
Domestic fowl chicks should be euthanized using a concentration of CO2 of at least 80% in air; higher concentrations (at least 90%) are required for newly hatched turkey poults and ratite chicks. However, such high concentrations of CO2 are aversive to adult birds. Adult chickens should be killed using approximately 50% CO2 in air. A mixture of 30% CO2 and 60% argon or 90% argon (with less than 5% residual oxygen) is effective and less aversive to adult chickens than CO2 alone. CO2 is not an acceptable method for killing waterfowl.
It is especially important to confirm death when birds are euthanized using gas, since they can appear dead but then regain consciousness. Containers in which birds are euthanized should be clear or have a window through which the birds can be observed.
When large numbers of poultry are to be killed, as during the depopulation of spent hen flocks, it is important that CO2 be injected frequently into the chamber to maintain these levels. A Modified Atmosphere Killing (MAK) System can easily be constructed for
CO2 killing of spent hens (Egg Industry, April 1998, pages 10-16). The MAK container holds about 200 hens when full.
• Carbon Monoxide (CO): Carbon monoxide is a relatively rapid and effective method of euthanasia for birds. Carbon monoxide combines with the hemoglobin in the red blood cells in preference to oxygen, causing hypoxia. Only a pure, commercially compressed source of CO should be used. Vehicle exhaust is not an acceptable source of CO for euthanasia because it is hot and contains contaminants. High levels of CO are deadly to humans, and chronic exposure of pregnant women to even low levels of CO can cause birth defects. Only well-trained personnel should therefore use carbon monoxide and then only under properly controlled circumstances. The gas should be delivered into tightly sealed containers and the area around the containers monitored for leakage. Depending on how many birds are being euthanized, a circulation system may be necessary to ensure that the gas does not become stratified.
• Gunshot: Larger birds like ratites can be euthanized by gunshot directly to the head, causing extensive damage to the brain. The gun must be correctly positioned to ensure that the brain is destroyed. Care must be taken to ensure human safety when using firearms. It is recommended that the carotid arteries and jugular veins be severed immediately afterwards to ensure death.
• Captive Bolt: Captive bolt pistols designed for livestock can be used to euthanize larger poultry species like waterfowl and ratites. The pistol should be applied correctly. Because there is motion after use of the captive bolt, it is advisable to restrain the bird to prevent injury to personnel. It is recommended that the carotid arteries and jugular veins of the bird be severed immediately afterwards to ensure death.
• Electrocution: Electrocution is a rapid and acceptable method of euthanasia provided that a sufficient current passes first through the brain to ensure unconsciousness, and then through the heart to induce cardiac arrest. Specialized equipment is required to ensure humaneness and personnel safety.
• Exsanguination/Decapitation: Birds can be killed by severing the jugular veins, carotid arteries, and trachea. Full decapitation also results in a rapid decrease in blood pressure and brain stem trauma. However the blood vessels may seal after being severed, delaying the onset of unconsciousness, and brain responses do persist for a brief period of time after decapitation. For this reason, exsanguination or decapitation should only be used as sole methods of euthanasia in extreme emergencies involving animal suffering where alternative methods are not feasible because of lack of equipment or trained personnel. Exsanguination and decapitation are acceptable methods of euthanasia when the bird is first stunned or anesthetized. Hand-held electrical stunning knives are available for stunning and exsanguinating chickens and turkeys, although these do pose personnel dangers if used in an area where there are wet surfaces. Birds can also be stunned first by administering a blow to the head.
• Maceration: Maceration in a high-speed grinder results in rapid death, and is considered a humane method for disposing of young chicks and embryonated eggs. Only grinders specifically designed for disposal of poultry, which have blades that turn at 5000 or more revolutions per minute, should be used for this purpose. The grinder should be properly maintained and must not be overloaded, since birds may be incompletely macerated under these circumstances.
• Anesthetic Overdose: When properly administered by the intraperitoneal route, barbiturate overdose produces rapid unconsciousness and anesthesia followed by respiratory depression and cardiac arrest. Federal regulations require these drugs to be purchased, stored, and used under the supervision of an individual registered with the US Drug Enforcement Agency (DEA). Poultry euthanized using barbiturates must be properly disposed of in accordance with state regulations.
Confirmation of loss of consciousness and death
Confirmation of death is critical regardless of the method chosen. The cessation of reflexes in the head area can be used to confirm loss of consciousness:
• Lack of response to a hard pinch delivered to the comb, wattles, or snood
• Lack of blink reflex when the eye is touched
The following signs can be used to confirm death:
• Cessation of respiration
• Cessation of heartbeat
Euthanasia Action Plan
All personnel that work with the birds, including transporters, should be trained in appropriate euthanasia methods and be provided with any equipment that might be necessary for euthanizing sick or injured birds or for on-farm depopulation. A written action plan for routine and emergency euthanasia should be developed and followed wherever birds are handled. Since improved euthanasia methods for poultry, and particularly for on-farm depopulation, are currently under development, the action plan should be reviewed and updated regularly to incorporate these new methods as appropriate.
Below is an example action plan for poultry euthanasia.
|EUTHANASIA ACTION PLAN
||J. Smith, Producer
Post this plan in a centralized area as a guideline for humane euthanasia of poultry on your farm. Remember to review the plan with any new employees, and also review the plan annually as a reminder to all personnel.
The Center for Animal Welfare
College of Agricultural and Environmental Sciences
University of California, Davis