What worked very well for me was a one way gate. I had them in the garage about 3 weeks. Then I took them to the run, sectioned off a corner with some lattice panels and a huddle box for shelter. The chicks were small enough to be able to go through it like water, the older birds could not. The first two days, I turned the big girls out of the run and locked them out. My set up lets me open the coop from the outside so they could still lay eggs in the coop.
By day 3 some of the chicks would explore out of the panel but staying close the panel. They quickly learned that was their safe zone, and retreat there quickly. A week later, they were eating with the big girls and there was no problems at all.
As Ridgerunner is fond of saying, we all have different experiences, so I will mention that my flock members have all been raised around chicks. My rooster has had chicks more than once. And even though it had been months since there were chicks, and some of the birds were the chicks, I kind of think they accept chicks more easily than a flock that are a one generational flock that birds have never been added to.
Mrs K