Hello, I had a flock of 9 chickens, all hens, ordered as chicks and received early June one year ago. These include a Golden Laced Cochin, Buff Brahma, Golden Comet, Rhode Island Red, Plymouth Rock, 2 Easter Eggers, and 2 White Leghorns. All of them grew up and got along fine, and have been living in a nice coop and run I built, since about August of last year when they were mature enough to be put outside. This is our first flock and they also enjoy free ranging our large fenced back yard occasionally. Memorial day this year in the morning, we found our Plymouth Rock dead in the run. I examined her carefully and she had no signs of any trauma. It was exceptionally hot the day before and overnight, so I speculated she might have had a heat stroke problem, but not sure if it was just a random thing since all the other birds where fine. The same day however, I purchased and mounted a thermostat controlled farm fan in the rafters of the run to provide a breeze to the corner of the run. The rest of the group seems to like it, and they will relax and sit in the breeze on a hot day now. I had a small fan in their coop blowing out from day one, and I since this issue, I ordered a larger axial fan, thermostat controlled, to vent the coop if it got hot. This won't kick on as much since it takes a while for the sun to heat the inside of the coop up, but is pretty noisy when it runs and sounds like a vacuum cleaner. The chickens use their nesting boxes and enter in and out and the noise doesn't seem to bother them. In the last week of July however, all the sudden, we find our one easter egger and one leghorn badly bullying the second biggest chicken in the flock, our buff brahma. The buff was experiencing increasing stress and would often hang out in the coop while the others would hang out in the run. I'd often find the buff panting real bad in the coop by herself. This bullying got worse, where the easter egger, and/or the leghorn, would hop on the buff's back and rip open skin on the back of her neck. The buff would just flatten out on the ground and let them do it. She is very docile, and also seems to become very broody as she'll hang out on everyone's eggs for long periods. Since this behavior we penned the two bully's together in a dog crate within the run for several days, and the Buff's stress level definitely seemed to drop as she mingled in the run with the rest of the birds. After several days with the bully's in the dog crate, I let them out a couple nights ago all together, and everyone seemed fine. It was evening and they started to roost so I let them out all night. The next morning they seemed fine, but from the house around 10am, we saw the Buff getting attacked again. This time they really got her and ripped a good 1" square of flesh off the back of her neck right below her head. It was deep and bloody down into and through muscle. I was going to stitch her up, but there was flesh missing to pull it together, so instead we just cleaned it out with hydrogen peroxide and it is scabbed over today. Her behavior seems okay, but we have isolated her in our house as she heals. And it is so deep, I'm concerned secondary complications might develop. We are adding Neosporin to the area also. I'm writing all this detail in case some chicken whisperer on the site can give me an idea of what is going on in the flock, and how I might stop this without culling/losing bully's or the victim. Our plan now is to let the Brahma heal for a week or so isolated in the house. Then isolate the bully's out of the flock for maybe a few weeks, and in this period re-introduce the Brahma to the flock. And then later, re-introduce the bully's. Reading many posts, we have done some other things such as adding a bale of straw to the run, hanging treat blocks, etc., in case they were just getting board, and to provide more shelter for the Buff. Anyway, if anyone has some insight or advice for this particular situation, please let us know.