Well, they followed their instincts. And yes, possums eat chickens. Everyone eats chickens... But possums usually rip them open and eat the heart and around the chest and leave the rest behind. Since only one is missing and nothing left over, it was something that took it. We have had hawks around. They are safe if they stay in the enclosure but the little ones have found ways to get out. And if they are out in the open, they are a perfect target...