YES We had a possum get in our CLOSED coop at night and kill our four pullets. Bit all the heads off first and then started eating one. He did not walk away. He just sat there as my husband opened the door. We were new to chicken keeping and you can bet we re checked and revamped and made darn sure they next batch were safe. We have had problems with dogs (as you may have seen on other posts) but not with possums since then. Now when we were out of town our friend was taking care of the chickens and he happened to come over to close the coop. This was after we had some new chickens. It was dusk and the chickens were in the coop on the top roost being very silent. There was a huge possum on the ground eating their feed. Well our friend made use of the nearest shovel as well. Worked great. Last one we have seen (in our yard anyway). DO NOT UNDERESTIMATE them!