CHICAGO • US agriculture officials seeking to control deadly bird flu have approved a method of killing infected poultry that entails sealing barns shut, turning up the heat and shutting off ventilation systems, an option that has been condemned by animal rights groups as cruel.
The Agriculture Department said in a statement that it would consider using the method if there are no other ways to kill flocks within 24 hours of infections being detected.
It wants to cull infected flocks within a day to prevent the virus from spreading. Nearly 50 million chickens and turkeys died from bird flu or were culled from December to June in the country's worst animal disease outbreak on record.
Shutting down ventilation systems in poultry houses"essentially bakes the birds to death," the Humane Society of the United States said. "We shouldn't compound the problems for birds by subjecting them to a particularly miserable and protracted means of euthanasia," said its chief veterinary officer, Mr Michael Blackwell.
The Agriculture Department said the method was a "necessary alternative" because of the need to eradicate the virus. It said its first choices for culling infected poultry would be suffocating them with foam or in chambers filled with carbon dioxide, methods widely used last spring.
More than two months have passed since the last infection. However, officials are preparing for a potential resurgence this autumn because wild ducks, which can carry the virus, will be migrating.
It takes about 30 to 40 minutes for birds to die from heat stress during the process, known as ventilation shutdown, said Mr T. J. Myers, the Agriculture Department's associate deputy administrator for veterinary services. He said the agency had not used the method before.