Sorry about your chicken

. I'd guess a raccoon. They usually kill at night, but it is possible he was out in the day, especially if he decided a chicken was an easy meal. Dogs normally kill by snapping the neck shaking the bird. Your puppy may be different, but I find it unlikely he got into the yard and out without someone noticing. As far as Greg goes, it doesn't really fit an opossum's MO. If they work up the guts to try and take down a full size chicken, and actually succeed in killing them, the remains tend to be a lot more... messy. As in the bird may be eviscerated, it may have detached body parts strewn around, etc. If it was a hawk, you'd either find a still living hen with a bloodied up back or no hen at all. Hawks take all or nothing. So that narrows us down to a raccoon, which I have had decapitate a chicken and leave the headless body. Raccoons can be real pills like that, killing something and only eating one part of it. I don't know about you, but while I absolutely hate losing a bird and will do everything I can to prevent it, I'm of the opinion that if something is going to kill it, they better well eat it and not waste it.