Mass depopulation is never easy. The first consideration in selecting the best method is the reason for the procedure. For example, if a communicable disease is present, especially one that can also infect humans, the method must consider human safety as well as animal welfare. Another example is a house that has been severely damaged by a storm, rendering it unsafe to enter in order to catch the birds. The type of housing is the next consideration, as recommended methods differ for birds in cages versus those grown on the floor.
If the birds are grown in floor houses, the American Veterinary Medical Association, as well as other groups, recommends the use of a water-based foam. For caged birds a gas — commonly carbon dioxide — is recommended.