I have 4 chicks about 6 weeks old. They are in a commodious screened-in coop during the day and have a roosting box (with a roosting bar and a nesting box inside) inside the larger coop for at night.

I realize they are too young to want to use the roosting bar, but at what age should I expect that they will automatically go into the roosting box?

Before when I had chickens it seems like they just marched up the ladder at dusk and I closed the door. These I've been putting inside each evening and closing them in. Am I doing right as a good mother hen would? Will they eventually go in on their own?