Let me start by saying. I AM A NEWBIE. I have 9 chickens, 2 Dominique, 2 Golden Buff, 2 Buff Laced Polish and 3 Silkies (1 is a Roo). All of them have been together since they hatched and I have had 0 problems out of any of them. They are all almost 6 months old. The day after I got my first egg..a bully problem started. One Dominique started pecking everyone. She eventually picked out half of BOTH Polish tail feathers causing bleeding. As soon as I discovered the problem I removed them from the flock and treated them. They stayed separated for 3 days until they stopped bleeding. I placed them under the coop in a pin before adding them back to the flock to they could adjust. The next day I let them out with the rest of them...no problems. 3 days later I had a bloody Polish..again. The Dominique continued to peck at everyone causing a major problem. I purchased wound spray and sprayed all the others to try and deter her...to no avail. I decided to remove her from the flock. The injured Polish has been with the rest of the flock after this injury (with Peck-No-More) with no problems. I kept the bully separated for 3 days before following the same re-introduction procedure. As soon as I let her in the run with the rest of the flock she immediately started again. How do I get this to stop? She has always been the dominant hen, but she has never acted this way. It was so sudden. I want them all to live in harmony and there is no reason why they can't. How long should I keep her separated? What products are recommended. It has been in the single digits so I haven't applied any deterrent spray. Which brand? Is this normal for their age and just started laying for her to turn into a bully? Sorry so long, but i wanted to include details to ensure the best responses. Thanks in advance!