We raise anywhere from four to ten broods a year, 22 eggs per incubation (Nurture Right 360) and the chicks go into a rotation: first 2-3 weeks in a brooder followed by the next 6 weeks in a chicken tractor. The tractors I've built have an attached coop that's 6' wide x 30" deep x 30" tall with a roost bar 6" off the floor. The chicks have NEVER naturally graduated to using the coops, preferring to huddle together in a corner of the tractor. I started putting their feeder in the coop just inside the doorway where they can easily see it, and that's helped. They still sleep in a huddled cuddle puddle in a corner of the tractor, but at least they know they have a coop, lol.
After they graduate (pullets to the main flock, cockerels to the freezer), they still seem to cluster together on the floor of the building- our main flock is housed in two large coop structures inside a 20x30 open-ended tractor shed. They eventually pick up the habit of either grabbing some space on the roosts inside the coops or on roost bars at the back of the structure.
Your chicks will figure it out. If you want to move the process along a little faster, put them in at night and shut the door so they can't get out. Then let them out in the morning.