https://www.backyardchickens.com/web/viewblog.php?id=2593-adding-to-your-flock
i read this article the other night, not that i'm planning to get any more (hee hee) and thought it was pretty good. It pretty much says what njchix said but in detail. We had a really rough experience with the new girls we got from her in Jan but i think our coop was too small. We actually wound up giving her one of our girls that was really beating up one of our new ones. We recently got a second coop and the older two are separated from the younger three at night still but free range during the day.
I have to admit it was a stressful experience. Establishing the pecking order is torture. The girl we gave to njchixs pulled all of the leg feathers out of two of the new ones to where their legs were bleeding and tore a hole in the third ones thigh. I actually had to do little surgery on the kitchen table! All are healed, feathers have grown back, wounds are healed, and cinderella is happy at her her new home.