So, once a sentinel chicken develops the antibodies, they're retired out to petting zoos or families in rural areas where the chickens continue lay eggs and live out their normal lives.
Sentinel chickens are used to detect the presence of naturally occurring viruses that cause West Nile and St. Louis encephalitis. Birds bitten by infected mosquitoes quickly develop telltale antibodies to the viruses. When large numbers of sentinel chickens test positive for these antibodies, scientists know there are enough infected mosquitoes on the wing to pose a human health problem.
The virus doesn't cause disease in the chickens and their eggs and meat are safe to consume, said Don Shroyer, medical entomologist with the Indian River Mosquito Control District in Vero Beach. In fact, he added, chickens raised for food by commercial farms can be exposed to mosquitoes bites and the same viruses.
Given all I've been reading about chickens being culled in India to try and control the spread of avian flu, it's nice to see how chickens are being used as proverbial canaries in coal mines to protect us humans from West Nile and encephalitis.
The sword cuts both ways, I guess.