Black and Green Duck

When my uncle and I went to the 2011 Deschutes county fair, we went to check out the birds they had there like ducks, geese, chickens, roosters, and turkeys. And there was this bird there that looked like a black duck with kind of a shade of green. But according to the sign on its cage, it said it was a chicken. But even I knew perfectly well that it was a duck because chickens don't have webbed feet. Do you guys agree that this is a duck?