My grow-out coop is elevated about two feet with a run attached. I lock the chicks in the coop section for a week or so before I give them access to the run. Sometimes when I open the pop door they are all on the ground within 15 minutes, sometimes it takes three days. They are pretty inconsistent in that. But one thing they are very consistent about, every night they go to bed under the pop door instead of going back into the coop for the first night and usually several more.
I think it’s because the coop is elevated. Until the chicks start to roost mine like to sleep on the coop floor or a very low spot. I don’t have this problem with my main coop or another small one on the ground that I sometimes use, but every time I switch chicks to my elevated grow-out coop the first night they sleep under the pop door on the ground.
After dark when they have settled down, I toss them inside the coop section and lock them in overnight. I’ve had chicks learn to go to bed inside that elevated coop after doing this once, I’ve had some take three weeks to get the message. Most of my broods are in the 15 to 25 chick range. What normally happens is that a few chicks start going to bed in the coop after a couple of nights doing this and all of them going inside after a week or just a couple of more days. I had one group only take one time before every chick learned, but that is really rare. And I’ve had some broods it took three weeks before the last two or three learned.
I have food and water inside the coop and inside the run both. I practically never see the chicks in the coop section during the day. They just don’t go in. If your only food or water was in the coop they probably would but that’s not how I do it.
From what I’ve seen your chicks are acting perfectly normal. If you want them to learn to sleep in the coop, lock them in there every night. They are usually pretty easy to just pick up once it gets fairly dark.
Good luck!