That is probably right. Bears are not really carnivorous in the same way a wolf or coyote is. They are omnivores and generally eat mostly berries, seed, termites, bees, fish and things like that. The will eat meat but it is usually in the form of carrion killed by other animals. Grizzly bear males will kill bison and elk calves if they have the opportunity though. Black bears are much more likely to be interested in the feed than the chickens.There's just about; no kind of coop that would keep a hungry bear out! What kind of coop do you have? And you say they only want the grain feed, not the chickens?? : (
http://www.americanbear.org/science.htm