I have 4 brown leghorns and 2 americaunas that are about a year old. They share a coop that is 4ft X8ft and a run that is 10ft X 8ft. Mostly they always get along just fine. But last week I added 2 Orpingtons that are 5 months old and about the same size. I put them into the coop at night up on the roost. The first day the older girls made the new ones stand in the corner of the run with theirs heads down in the dirt. I didnt interfer with the whole pecking order thing. But the second day the older ones started pecking at one of the new ones til she was bleeding above her tail. I took her out to a separate area and put the other back into the coop where they wouldnt bother her. Later in the day I found her outside again with blood all over her. They pecked above her tail and all around her vent. Nearly pecked her tail totally off. Not the feathers....her actual tail. I have removed her and treated her all week and she is luckily recovering very well. I thought for sure she would die from the injuries. My questions are about mixing flocks and how to not let this happen again. I had a similar situation when I added the americaunas in with the leghorns last year. It took weeks to finally get them together without pecking and serious wounds. The americaunas are definitely low on the pecking order. And yesterday I saw a wound on one of the americaunas again. IF I can determine which hen is pecking others, do I need to cull her from the flock?? Debeaking her is just to cruel. I would like to extend my run to double size and add more chickens of different breeds but I sure dont want to go thru all this again. Any advice would be greatly appreciated!