Somerset, Pennsylvania - Henrietta the chicken was living inconspicuously for 18 months among 36 000 other chickens at Brendle Farms - until a farm foreman discovered she had four legs.
Farm-owner Mike Brendle was amazed by the discovery among his standard two-legged, egg-laying hens.
"It's as healthy as the rest," he said.
Brendle's 13-year-old daughter, Ashley, named the bird Henrietta after the discovery. It has two normal front legs and, behind those, two more feet. They are of a similar size to the chicken's front legs, but do not function. The chicken drags her extra feet behind her.
Brendle said he has never seen a chicken with four legs before. He moves 36 000 chickens through his farm three times a year and has been farming for 30 years.
There is no definitive reason behind such deformities, said Cliff Thompson, a retired professor of genetics at the University of Pittsburgh at Johnstown. He said it could be an accident of development, akin to a sixth toe on a cat.
Brendle said he jokingly suggested to his family they sell Henrietta in an Internet auction, but Ashley objected. - Sapa-AP