After a month of quarantine, you will need to integrate. We have a box built into the side of our coop. Basically, a 14 inch wide by 5 foot area that has a roof. We store things on top, and usually keep it open, but when we are integrating or have a sick chicken, we put them in to the "brooder or sick area". This keeps them seperate but allows everyone to get to know each other. Two weeks of seeing each other but no touching. Then we start opening the door and mingling everyone with us out watching.
This is a pic of me watching with my squirter....
I watch an squirt aggresive behaviour for 2 to 3 days. After that, the job is usually done.
If you do not have a seperated area in your coop, get a wire cage to place the new girls in. It works just as well. The key is allowing everyone to get to know each other from the safety of barrier. See but not touch. Oh, and have lots of patience.....
Our seperate area for new girls or sick girls....
Good Luck!! It can be nerve racking but will work out in the end...