Nearly 7 million chickens and turkeys in 13 states have been killed this year due to avian influenza, prompting officials and farmers to acknowledge that, despite their best efforts, stopping the disease from infecting poultry is incredibly difficult.
Spread of the disease is largely blamed on the droppings of wild birds, such as ducks and geese, which often show no signs of illness. But studies suggest the virus can be tracked into secure chicken and turkey barns on equipment, workers, mice, small birds, and even dust particles.
