Personally I think its a bad idea. Mad cow came about by feeding ground cow scraps to cows in cow feed. A well known / Brand name producer of corn based cow feed was using cow bones and scraps to fortify its feed. There was also a news article on dogs becoming sick from dog food made in china. The dog food was fortified with ground up animal bones from the local animal shelters.
Human cannibals that eat people on a regular basis begin presenting signs of neurological problems such as ticks and loss of coordination. I don't believe were meant to eat our own kind and that doing so can cause issues down the road. I believe this is true for most animals. Since I intend to use my chickens for my own food supply, I am not comfortable feeding them chicken.
Personal opinion
Riki
Hmmm I wonder if the neurological problems are due to the cannibalism or because the practice mainly exists within small, isolated communities with very little contact with the outside world (inbreeding) and a limited diet as well. If they had access to other types of meat and an otherwise balanced diet, with human meat added in, I wonder if the neurological problems would still develop. Now I'm intrigued... I'll have to ask my husband. He's an anthropologist.