Mine didn't want to go in at night at first, either. We just kept putting them in the pop door at night and after about a week, they all were in the coop safe and cozy when we went up to put them in. It just took a little while.
As for a light, how about one of the battery operated tap...
I would put my chicks, one at a time, each night for about a week, and put each in the coop allowing them to 'climb' the ladder. I did not use an open ladder though. I used a board with ladder 'rungs'. It took about a week but once they got the hang of it, they went in by themselves every...