Good idea. The nest boxes are currently closed off from the inside so the chicks don't get in the habit of sleeping in there. I think I have a couple hasps laying around that I can put on them.
When we bought our custom pre-built 4x6 coop at the feed store we had no say on its design. The builder had the one perch at the same level as the nestboxes on the opposite side. So naturally all our hens immediately took to sleeping in the round-holed entrance nestboxes - nice cozy secluded sleeping quarters. There was no way to break them of the habit since the perch was not higher than the nestboxes so we just make sure to clean the boxes in the morning and add new straw as needed. Your chicks as adults will eventually use the higher roost bar for sleeping rather than the floor height nestboxes. The only way they'd use the boxes is if there wasn't enough room on the perch for all of them to fit.
Our 4x6 is too small even for a couple bantams and we quickly allowed our 4 hens to learn how to free-range, set up a popup canopy, a couple of makeshif lean-to's, a big doghouse, and bushes to hide/snooze under during the day. Other than using the coop to lay their eggs or roost for the night the girls are always out in the yard somewhere. Cooper's Hawk made his rounds again today sitting on the fence watching them but they're too savvy to let him/her get them. We don't have chicks for easy predator pickings and the adult hens, even the Silkies, are too smart to stay in the open. One dove into the doghouse, one dove under the wheelbarrow, one was sounding the alarm under the canopy and one was in a nestbox brooding - pretty savvy girls for not having a roo for protection. The Hawk much prefers going after the easier wild birds which is why we keep a wild feeder to lure his/her attention away from the hens. There was a hen in the open but he preferred going midflight after an easy Mourning Dove instead - she was too quick for him though and he moved on!