Are Chickens Cannibals?

I swear chickens are cannibals, i was at my uncles farm and my cousin didn't want to finish his plate of chicken, which was killed from the coop and freshly served up, so i took it since i already at mine i threw it in the pen and all the chickens went crazy and started fighting each other for the meat! Is this proof of Chicken on chicken cannibalism? I'm dead serious by the way.