I have a light with a dimmer switch on the outside of coop in weather-proof box. I asked DH to install the dimmer switch because I didm't like the idea of the light "suddenly" going out and the girls having to fumble finding the roosts and such. Another reason for the dimmer switch is because they get up and around if I turn on the light full bright after they have settled down. During the winter months we turn on the light before dusk and then around 9 pm we dim it. It takes about 15 mins for the last one to mosey onto the roost. I watch them through the window and then turn the light off. DH has them trained to move much faster though. He flashes the light and they hustle to get up on roosts. It's funny. They know he has no patience. The downfall is the coop gets messier and they eat more food. This summer we are going to add a light to the run so they won't spend as much time inside. It will be on a timer to go off around 8:30pm. I don't use the light just for eggs, although that is a plus. I do it because the girls seem to like the longer days of summer and winter days are just so short. BTW, in March, we stopped using the light since the days were starting to get longer and I figured they needed a break from egg laying and a "short" winter season. The egg production dropped by over a half and they went into a molt. That might be a plus too, since they didn't lose feathers in the fall when it was cold and they needed them.