Very pretty birds.
As for the aggression, it's just one of those things that happens when a newbie is added to the flock. I hate watching them establishing pecking order, and am probably the worst one in going out to break up fights. I always try to protect the one that is getting picked upon. Can't they all just get along! they can once everyone knows their place, or how to hide behind momma.
The quickest and easiest way to calm things down is pen the aggressor. A few days in jail and the new girl will feel a bit more secure and stand up to her. Fight will be over quickly and each will have an established place within the flock. At least that's how I've always dealt with it.
Whatever you do they will eventually have it worked out. I never though our poor Harvey girl was going to be accepted back into the flock, but now she leads and the others follow. Harvey was attacked by an older and much bigger turkey. She had half her face ripped to spreads and ended up blind in one eye as I couldn't reattach the muscles to work the eye lids. She spent about three months healing from her ordeal and was separated from the others during this time. I was very concerned about reintegrating her, but all is well. My Harvey girl is very hyper vigilant and moves away from the slightest touch unless she knows its me. I love My Harvey girl. In the end we had to let her find her place in the flock.