Man, my poor hens have been through the ringer. I just got my surviving 8 over a really serious respiratory infection and now I've lost yet another, this time to some predator attack. I have no clue how the critter got in. My chicken run and coop is chain link on three sides (with the fencing buried a foot under the ground) and the wall of my friend's house on the fourth side. The top is covered by bird netting which is secured with zip ties. I haven't had any problems with this arrangement for over a year. The coop door is always open--the chickens can run in and out freely, because I don't get over there until around 10 every morning to let them out of their run and into the 1/2 acre of fenced yard. There is a wooden and hardware cloth gate that I built myself that keeps the run closed at night. My only guess is that the animal that did this somehow found a weakness in my bird netting top. With my run's configuration and the present fencing, there's really no better solution, so I guess I'll be adding more zip ties. The other possibility is that a rat did this. I have seen a rat around, and have been neglectful of trapping it. I'll see it run out and eat some food and then return to its hole. I never thought a small rat like that could kill a 7 lb. chicken. The chicken that was killed had her head torn off and her abdomen ripped open. She was very neatly "cleaned" of all of her insides. Literally--her body cavity was scraped down to the bone. Does this sound like a coon or possum? I'm almost certain a rat couldn't have managed this. I'm going to set three or four live traps around the run tonight and possibly camp out. I can't stand to lose anymore hens than I already have in the past month.