I don't know if they can see in the dark or not. I don't think you need at light unless you are using it for heat and then I would use one of those red ones. There are all kinds on theories on whether you should have "supplemental" light in the coop. Mine never had it. They continued to lay fine, except for a little over month from Christmas to Valentines day. Now we are back to 3-5 eggs a day from 5 of them
My middle younger brother swears chickens cannot see in the dark. I don't think they need light to sleep, however. Unless you have tropical chickens, you wouldn't need light in the coop at night except for heat. Most chickens are more cold hardy than heat tolerant. Hope that helped.
Chickens can't see in the dark - it's why they instictively get to the roosts before dark. I've seen some of mine, who all free range, return to the coop while it's still a little light outside but then they step inside coop and it's too dark for them to see to climb up ladder to roost. They get really panicky and fall off ladder, fly into walls, etc.. I put a light in coop that I leave on till everyone is on roosts and then it's lights out. Only have to do this in winter. In summer, it stays lighter longer and there's enough light in coop for them to see. Chickens will not get up in the dark and move around. They will however get up if there is a light on.
My recommendation is to let them get a good night's sleep with no lights.
Does your coop have natural lighting through the windows? My window didn't allow light in and we had trouble when they first started laying. They laid real early and couldn't see to get to the nest boxes and were laying where ever they were. We also had a lot of rubber eggs. I put in one of those 7 1/2 watt bulbs and they started using the nest boxes and had hard shelled eggs. So if your coop has enough moonlight to see by they should be fine, if not they will let you know when they start laying. Mine didn't have any trouble until they started laying.
I've read that they don't see well in darkness at all, and that's why they head for the safety of their coop roosts at dusk. They'd be at a distinct disadvantage against predators if they can't see them.
Windows...well, my DH feels like they have enough ventilation from where the roof attaches to the coop. He drilled holes into 2x4/s, so I'm afraid it will be dark even at daybreak. The cheapest window we could find was $70. I thought about cutting out the wall and replacing it with screen and then putting hinges on the wall section to close and open (I saw something similar on the site). But...if they're supposed to be locked up tight at night, then that idea wouldn't supply them with any early light anyway.