There actually was a real headless chicken that travelled around with its owner to fairs and similar shows many years ago in the United States. Apparently he fed it with a dropper into a small hole in the neck. I think this was in the 1940's or 1950's maybe even earlier.
Growing up in Arkansas, my mom often told us about how they would ring off the heads of chickens to kill them before eating, only to have their bodies continue to dance around for a few minutes more. Of course, that was simply a nerve and muscle response; for the most part anyway.