They are ferel(domestic gone wild) chickens from Key West. They are in a similar situation as the Mustang horses out west. Pretty birds, but unwanted by some of the locals. LOL. Unwanted by the chicken haters.. People are actually being paid to trap and remove them because so many people put up a fuss. Good hardy birds. I have a friend who bought like 200 of them to free range on his property as yard ornament, bug-eating, chickens.
Google Key West Chickens and you will get quite a bit of reading, not to mention a bunch of pretty pictures.
LOL. Key West is in a war over these little guys. Wire traps are set to catch them and the chicken-lovers run around and spring the traps or let the birds out. The chicken-haters get rid of them any means neccessary. You know the usual complaints from chicken-haters "they're too loud", "they are tearing up my lawn", "I'm tired of stepping in the mess". LOL.
I think the whole thing is silly, and yes, I have heard of that type of chicken. Most people do consider them they're own breed(kind of like the Mustang horses) and I find them very attractive.
-Kim