I've had great luck integrating new babies into my flock. I bought a small rabbit hutch with attached run that sits on the ground and the babies go in for a minimum 2 weeks inside my existing chicken run. This way the older girls can get used to seeing the newbies and vice versa. After that, I raise up the run portion of the hutch with bricks so that the babies can start venturing out but have a place to run when they start getting pecked. After about a month, everyone is used to each other and I'll find all of the babies (I guess they would be teenagers by that point right?) in roosting with the big girls. I usually leave the hutch in place until I can transition the babies to adult food. Then it gets stored in the shed for the next time we get babies.
Here is the hutch I bought: https://www.amazon.com/Pawhut-Woode...qid=1470704360&sr=8-133&keywords=rabbit+hutch
Good luck!
Here is the hutch I bought: https://www.amazon.com/Pawhut-Woode...qid=1470704360&sr=8-133&keywords=rabbit+hutch
Good luck!