I hatch my own chicks. I keep them in a tub brooder in the house 1 week-10days. I probably should just brood them entirely in the brooder house like we did when I was a kid, but I like to watch my babies. After a week they start eating to much and start getting stinky.
Then they go into their own brooder house, it has a tractor of its own that I put next to it. When they go outside they get locked in for a day or 2, then I open the poop door and let them into the tractor run. They soon learn that they can stand in the poop door and breath fresh air. Sooner or later someone pushes someone out the door and the first thing you know they are investigating their expanded world. I tractor them around to grassy areas of the yard as they grow, so they can scratch for bug and eat grass, I coarse grind seeds and toss it in the gras. When they are big enough not to crawl under the fence and go into the neighbor field, then I move out the tractor and they get to investigate their own Brooder House Run. THey will stay there or move on to a grow out house until they are at Point of Lay.
Fresh air keeps them healthy, why haven't you brought them outside yet? Little excursions are good for them. Make sure you bring their food and water for their daily excursions. They will also need a shady area to stay out of the sun if need be.
Chicks can take a lot of heat, more so than hens. Mine are now 5 weeks old and have not been phased by 108 degree heat index for more than a week.
Enjoy your chicks, I do 4 times a year.