Opossums love crunchy things like egg shells and heads. They will bite off the head, and stash the body. We had a opossum eating eggs for a week from our hen house...found the critter curled up sleeping in a nest box one day. Early that evening, apparently it came in the little coop door, tried to get an egg from our sweet broody bantam,Clover, and decapitated her. Then it stashed her fat little body under the hen house, and came back for the eggs. My husband found it just as it was going back into the nest box.
Awful, isn't it!
I put rat bait out, it took some the first night, more the next night, then never came back.