We have had a productive trouble free flock for over a year now. (Thanks to all the great advice I have read in the BYC forum.) We have a hen house but our hens have free roam of the yard. We have four dogs and a cat, none of which have ever bothered the chickens. Last weekend I found three dead chickens, feathers everywhere and one missing. I could see some small puncture wounds on the necks. The bodies were not in one area, they were scattered over the yard which is fairly large. I never found the fourth chicken. The dogs had not been let out yet and we assumed is was a fox so I beefed up the coop area. I also sat up that night waiting for it to return, nothing. I did see a Possum and a cat that showed up at the neighbors a few days before but nothing in our yard. My daughter said she heard a loud commotion around 9am. A week goes by, no tracks, no dig marks and no predator sightings. I left the house today around 9:50 AM and got back around 11:15 AM. Lo and behold there is a dead hen just off the back porch. I looked her over and saw one puncture mark at the base of her neck by the spine and what looked like more damage on the spine closer to the rear end. Most of her feathers were intact. I called the neighbor and he said that around 10:30 AM he let his dogs out and they ran towards my fence barking. It took him a minute to gather his shoes and he went out to investigate. He said he saw the hen on the ground still alive but in the process of expiring and the larger hen pecking at the dying one. While I was talking to him I noticed the new stray cat lingering by the back fence. So here is my quandary. My neighbor who also keeps BYC thinks the larger hen killed the younger one. This would not explain the missing hen from earlier in the week. Also would a hen go on a killing spree of multiple chickens in one day? Does the injuries I described match that of an attack from a chicken? One of the first chickens killed was the dominant female. Should I still be suspecting a fox or could the new stray cat be the culprit? The cat doesn't seem very large so initially I ignored it. I had never suspected the Possum because I didn't think they were agile enough to catch an awake/alert chicken and have never known them to leave a kill uneaten. Thoughts?