I'm a newbie to BYC and chicken keeping, but I cared for a large variety of birds in the zoo field for about ten years, so I have a bit of knowledge in the area of introducing birds to each other. My current chicken situation is a bit different from yours, but you might be able to get some ideas from my plan for my upcoming chicken introductions. I have one adult hen and will be introducing three chicks to her once they are able to handle outdoor temperatures and are off of their chick diet. My adult is a bantam and was picked on by her larger coopmates in her former home. By the time my chicks are ready for introduction, they will be larger than my adult hen. I'm also assuming that the chicks will have the advantage of already being part of a flock. I want my adult hen to have the home field advantage when she is introduced to her new, larger coopmates, so I'll be moving her into the coop as soon as I'm done constructing it (which will hopefully be by this weekend). Once my chicks are able to be outside, I'll have them in a hutch next to the coop. I'll keep them there until they're ready to switch to the adult chicken diet. I do expect squabbles during the introduction, but hopefully everybody will settle in to a nice pecking order without too much trauma. I don't think my adult hen will end up being at the top of the pecking order, but I do want her to start the game with a nice advantage so she won't get completely beat up.
We'll see...
