We started off with 5 girls, as soon as we put them in their new home the bullying started. it was so bad that 1 hen died. We rehomed the one we felt was the worst bully, she went to a lady with acres for her hens.
The remaining 3 were still at it though. We had 3 very bloodied & featherless girls. They would really shriek when feathers were pulled. We did everything suggested on this site & numerous others, less treats, more treats, additives, spray, the list of things we tried seems endless. We even built a second tier in part of their run even though we knew they had ample space already.
We had looked at beak bits but just thought they were wrong somehow. In deperation went to the vet. At first he thought they might have mites but on examination found then completely free from bugs or nasties of any sort. His advice, get 3 more hens! We had read this somewhere on the web so off we went & bought 3 more. We now had 6 hens getting feathers pulled & screaming.
Finally we secumbed & bought the beak bits (white plastic type). We just put these on our 3 remaing original girls. The change was immediate. No more feather pulling or feather eating, just 6 very happy girls. No more shreiking just the odd bit of natural pecking order aggro. We are getting 4-6 eggs per day & the girls all look good & healthy.
We look at our 3 new girls & they are so much calmer than the first 5 hens ever were, so think we bought hens that were already stressed for some reason the first time. If this hadn't worked we would have given up on hen keeping. Please no nasty comments about us using bits, if you haven't had a problem this bad you have no idea what it is like watching your hens destroy each other & feeling so helpless about changing the situation.