Yes he was real. In fact if he was alive today he could probably get elected to the senate from NY.
"Just six weeks after his beheading, Mike was featured in a Life magazine article and his fame grew. For just 25 cents, anyone could pay to get a look at Mike. At the height of his popularity, Mike was raking in a cool $4,500 per month, which was no small potatoes in those days. They probably would have thrown in his head as a bonus - it was stored in a canning jar and toured along with Mike. (Actually, a cat ate Mike’s head. Some other poor chicken’s head was pickled in the jar.)"
[url]http://home.nycap.rr.com/useless/headless_chicken/[/url]