The AVMA supports the use of water-based foam as a method of mass depopulation for poultry in accord with the conditions and performance standards outlined by the US Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS). The following summarizes the conditions under which USDA-APHIS has approved the use of water-based foam for depopulation of poultry:
- Use of water-based foam is considered an appropriate method of depopulation of floor-reared poultry (i.e., broiler chickens and turkeys) in accord with USDA-APHIS performance standards ("USDA-APHIS Performance Standards for the Use of Water-Based Foam as a Method of Mass Depopulation of Domestic Poultry" [Attachment A]); and
- Animals are infected with a potentially zoonotic disease; or
- Animals are experiencing an outbreak of a rapidly spreading infectious disease that, in the opinion of state or federal regulatory officials, cannot be contained by conventional or currently accepted means of depopulation; or
- Animals are housed in structurally unsound buildings that would be hazardous for human entry, such as those that may result from a natural disaster.
Mass depopulation refers to methods by which large numbers of animals must be destroyed quickly and efficiently with as much consideration given to the welfare of the animals as practicable, but where the circumstances and tasks facing those doing the depopulation are understood to be extenuating. Euthanasia involves transitioning an animal to death in a manner that is as painless and stress-free as possible. The AVMA currently considers that destruction of poultry using water-based foam is a method of mass depopulation and not a form of euthanasia. The AVMA supports additional research to evaluate whether water-based foam can be accepted as a form of euthanasia.
USDA APHIS Performance Standards for the Use of Water-based Foam as a Method of Mass Depopulation of Domestic Poultry
(These dynamic Performance Standards are currently based on objective and subjective measurement. They are intended to be guidelines used to evaluate any type of water-based foam and foam delivery system used for depopulation of poultry until such time that sufficient biometric, engineering, and welfare data can be gathered to establish thorough performance standards.)
- In order to comply with current animal welfare considerations and optimal operating procedures, USDA APHIS has developed these minimum standards which all water-based foam systems used for mass depopulation of poultry must meet or exceed by performance measurement until further notice. The field application of water-based foam used for depopulation as stipulated by these standards is currently approved for use with floor-reared poultry and as conditionally stipulated in Standard 11. Floor-reared poultry is defined as poultry not housed in cages (e.g. broiler chickens and turkeys), but may not necessarily include all types of poultry (e.g. waterfowl, see Standard 11). Approved experimental protocols to adapt this method for use in caged poultry (e.g. laying hens) and broaden its application to other poultry types are not restricted by the official position of USDA APHIS on the use of water-based foam for depopulation of poultry nor these standards. Note that these standards will be revised as further information becomes available.
- Water-based foams used for depopulation must be:
- readily available;
- environmentally safe;
- compatible with carcass disposal methods;
- as non-irritating as possible to poultry mucosa; and
- of no significant risk to human health
- Foam delivery systems must produce foam that is of the appropriate consistency and density to completely occlude the upper airway of domestic poultry; so that when immersed in the foam, airway occlusion occurs in a rapid and overwhelming manner such that birds do not unduly struggle. At this time, the desired bubble size from water-based foam used for poultry depopulation should not exceed 0.625 inches (1.58 cm) and preferably should be smaller. Note: Bubble diameters exceeding 0.33 inches (0.84 cm) may not be appropriate for the depopulation of all types of poultry or may not provide 100% depopulation of the target birds. It is intended that systems developed pursuant to this Standard will provide broad species depopulation capability, but may be limited by the developer to specific species or applications. If the foam used to depopulate does not meet the requirements as stipulated in Standard 9, then its use must be limited to those types of poultry where it has been shown to meet the criteria in Standard 9.
- The water-based foam must be fluid enough:
Fluidity in foam is equated to the expansion ratio and the moisture content; to be suitable for depopulation of poultry, the expansion ratio required ranges from 25:1 to 140:1. Note that foams exhibiting expansion ratios exceeding 120:1 may not be appropriate for depopulating all types of floor-reared poultry. Importantly, foam exhibiting expansion ratios below approximately 35:1 may not accumulate to sufficient depth to cover the target species. If the foam used to depopulate does not meet the requirements as stipulated in Standard 9, then its use must be limited to those types of poultry where it has been shown to meet the criteria stipulated in Standard 9.
- to engulf or negotiate any building supports or structures,
- to surround the birds without cavitations that may be generated by bird movement, and
- be of a consistency (fluidity) that is readily inspired by the birds.
- The water-based foam must have sufficient body to be able to accumulate to at least 6 inches (15 cm) over the mean height of the types of poultry being depopulated. In cases such as full grown turkeys depths up to at least 54 inches (137 cm) may be required.
- The application of the water-based foam must be performed in a manner that disturbs the birds as little as possible and avoids panic, "piling" or overcrowding.
- Water-based foam of the proper consistency as outlined in sections 2-4 must be capable of being generated using a wide variety of water qualities across a broad range of dissolved solids, salinities, pH, and hardness factors. It is important to note that at present, the primary limiting factor of the speed at which the depopulation event can be conducted, is the availability of an adequate water supply at the site of depopulation.
- Water-based foam must demonstrate a residency time (persistence) of no less than 30 minutes (regardless of climatic conditions or solar exposure) to ensure that all birds have been properly dispatched.
- In terms of the time to death and total percentage of the population killed when water-based foam is used on any type or age of poultry, the foam system employed must result in the death of 95% of the birds within 7 minutes or less after the birds have been completely submerged in the foam. If 100% of the birds have not been depopulated after 15 minutes post-submergence, then contingencies must exist to dispatch the birds as humanely and quickly as possible in accordance to currently accepted euthanasia methods.
- Water-based foam delivery systems must perform reliably and reproducibly in accordance with the criteria detailed in performance Standards 2-9 under a wide range of climatic and operating conditions. Climatic conditions may include ambient indoor temperatures ranging from 0° C (32° F) to 44° C (110° F) and relative humidity ranging from 10% to 100%. Poultry housing situations vary widely including large surface areas and multistory housing. Strategies must be developed to address these variances before attempting to depopulate with foam.
- There are many species of fowl, including waterfowl (e.g. ducks and geese) and other gallinaceous birds (e.g. guineas and quail) used for food, eggs, or other purposes where current data on the use of water-based foam for depopulation are lacking. However, water-based foam may be conditionally used in depopulating these particular types of fowl if:
However during the foaming of species where reaction to foam is unknown, if adverse reactions are observed that are more extreme than those seen with farm-reared poultry (i.e. broiler chickens or turkeys), or prolonged killing times or killing rates not consistent with Standard 9 are encountered, then foam should not be used to depopulate that particular species of fowl. If a question of suitability on the use of foam in a particular species arises, then the determination of whether foam may be applied to a particular species will be made by the USDA Incident Commander and the ranking USDA Animal Welfare officer detailed to the outbreak, or the State Veterinarian.
- the foam and delivery system meets the criteria detailed in Standards 2-10 and,
- the system demonstrates killing times, killing rates, behavioral responses, and physiological responses comparable to those which would normally be observed when water-based foam is used to depopulate common farm-reared poultry where foaming has been shown to be effective (i.e. broiler chickens and turkeys).
- Components of water-based foam delivery systems must be able to withstand chemical disinfection, and all parts of the water-based foam delivery system that enter contaminated houses must be able to withstand stringent cleaning and decontamination measures. In some cases the water-based foam may also be used for decontamination purposes.
- Water-based foam delivery systems should either be adaptable for multiple types of poultry housing or be marketed for use that is limited to specific types of poultry and/or housing.
- Water-based foam delivery systems should be portable and constructed of components that are easily serviceable and/or replaceable. Portable by this standard is intended to mean easily transportable from one site to another by any conventional means.