I believe in a headless chicken running around for a days tops... but 18 months? That's rather bull... I mean... despite the loss of blood fact, it can't eat, it can't drink, it'll die real soon in less than a week.
this is rllly old...dunno if its the same one...but ye there was this one where the farmer accidentely chopped the head off the chicken while he was choppin wood or somethin....the chicken lived for a few years...cause it choked on day on a corn kernel
IT could well be true as the chicken has a nervous system that is alot slower than humans. This chicken could have had a really slow nervous sytem which took it 18 months to tell the other parts oif the body. "OH F*$k, I'm dead".