I had multi aged chick groups last year and used a wire dog crate with small door for the littles too, it works great....by the time the littles are too big to fit thru the door they are pretty well integrated.
Agreed! I wish I had thought of it when I first brought the buffs home instead of a week later. They got trampled quite a bit by the bigger ones. I can see they definitely enjoy having their own escape area. What cracks me up is watching the barred rocks and silkies get in there with the little ones to "mother hen" them.