Chickens also coming off the nonstop heat lamp have a panic session and literally are afraid of the dark for what seems like a week. When mine were getting big we moved them to the coop, and as the sun went down, even though they were locked in, they'd all fly up to the vents and hang out in the window and start crying and cramming themselves to be close to the light. And they would start at dusk like clockwork. Kind of amusing actually.
Eventually, they stopped crying, but they kept not using their roost bars and going to the vents until eventually, they were to big. Now they're a year older.
We recently added 3 babies, who I have in a special enclosure I built so the flock can see them, but not harm them. And moved them out from the heat lamp and to that enclosure with one of those heat walls. They are happy all day long to watch the big chickens and scratch grass.
But as soon as the sun starts going down, the panic session starts.
It will pass.