Kathy your chickens are behaving exactly like I'd expect chickens that age to act. You can always find some exceptions but in general immature chickens are afraid of mature chickens until the younger ones reach a certain level of maturity. For a good reason, the older chickens are likely to peck them if the younger ones invade their personal space. Mine are most aggressive about that as they are settling down for the night and almost never sleep on the main roosts with the adults until about the time they start to lay. Until then they sleep somewhere other than the main roosts. During the day the young ones make sure they are somewhere the adults are not.
I don't know how your new roost is situated relative to the old one but it may not be far enough away horizontally that the older hens cannot reach them. It may be too close for comfort.
With that type of ages I don't expect them to mingle that much at all. I consider it a successful integration if the young ones are not getting hurt. It sounds like you have accomplished that in what I consider a pretty small area so I think you have done well. Just don't expect them to be one tight flock until the young begin to lay.
I don't know how your new roost is situated relative to the old one but it may not be far enough away horizontally that the older hens cannot reach them. It may be too close for comfort.
With that type of ages I don't expect them to mingle that much at all. I consider it a successful integration if the young ones are not getting hurt. It sounds like you have accomplished that in what I consider a pretty small area so I think you have done well. Just don't expect them to be one tight flock until the young begin to lay.