I put my 4 and 5 week olds into the coop last weekend. I did it during the day and put a light in there for them, for both heat and light. They seem to be doing OK. They were scared to be moved (bunch of "chickens"), but since there are 26 of them and they are all together, they seemed to take the move pretty well once they were in there. It's been 3 days and they are running around, pooping and eating and having a great time. One time I did turn off the light (thinking it would be no big deal because they get some daylight inside the coop) and they all ran into the corner and freaked out. So, for the OP, it is likely it was mainly being in a new place in the dark that caused the big freak out. I know they are enjoying the room to fly around and run in.