mean chickens

We recently got a mille fleur and she is little and sweet. It seems the other 6 girls are not as found of her as i am. I have 3 that always peck at her or pick her up by her feathers. Is there anything i can do to get this to stop. Ive tired to tell them no or make a loud " uhunt uh" but now they are seeming like they are jumpy and run when i come out side. What to do...

Hello! I am new, but I also have mean girls! Especially when they're either broody or there's a new addition. From what I've read as well as my own personal experience ,you should introduce a new bird to your existing flock slowly. (This is of course after you've kept the new one separated for awhile;as to make sure they don't bring any funk into the flock. I've heard different lengths of time. And I personally did not do this). So,this is what I'm doing now,I have 12 new chicks. 6 days old. My 2 broodies are super aggressive right now. They have chicks of their own and are currently setting on another clutch each! They hate any new bird,any age. I've separated the pullet chicks in a medium sized dog carrier. And they're in the coop during the day and inside warm at night. Eventually,they'll stay in the coop. My husband and I made a little chicken tractor too so they can scratch and eat bugs out with the others,but not get beat up. It works well as a chance for all of them to get to know each other. And except that they are staying! As far as when I actually pshysically introduce..... This will also be slow,and supervised! . And eventually,they'll work out their own pecking order. But the chicks will be bigger and everyone more adjusted to one another. I hope this in some way helps. I've even heard of the chicks pecking at the big girls once together! lol. Anywho,would love to stay updated. I truly hope you have success. God Bless!