Chickens are very instinctive and they will be fine. Over time they will do better but if you watch there will always be an understanding between the two groups. As humans we always want to help the little guy. We cheer the under dog. Chickens have a very different social structure, they demand...
As the younger ones mature they will flex there muscles and lose some of there feathers and find there place in the Pecking order. Even if they are about the same size they still need to mature. The more we interfere the longer it will take.