I always have a separate coop with enclosed run for younger new chickens. This year should be interesting because our two coops are 3/4 full of 1 year-2 year-3 year chickens. We have a very large dog house that is divided into two parts ( that our Great Pyrenees never used) we are going to make some perches across the furthest section and add a box in the first section for eggs, we are enclosing that with a 10x10’ steel dog run. We are getting 4 cream Legbar chicks in early May and this will be their home from the time they can go outside and until the end of summer. The rest of my chickens free range so they can look them over for a few months. I hope this solution will work, and everything will go smoothly. The breed of chicken I found loved to search out younger, smaller hens was my Welsummer hen, Wilma. I had heard these were pretty laid back. She was downright mean, actually would hunt for them and would target them, pecking and chasing them. Luckily our rooster would step between them most of the time.
I was looking into getting more chickens when I realized that I would have to mix them together at one point with the older ones. This article helps a lot and I will be sure to use these methods when they come of age to do so.