This is our first year with chickens so I was unsure about the lights, but I always talk to this chicken farmer at the Farmers Market when I have questions. According to him, a compact fluorescent bulb that is equal to a 60 watt is fine (that's what we are using). He told me to look at a sunset calendar online and then count back 13 hours from sunset and have the light go on at that time. Then, in a month or so, we will up that to 15 hours before sunset. Once the sun is fully up (he said 8:30am), the light can go off. So we set a timer that has the light turning on at 5:15am right now and going off at 8:30am. Hope this helps. Some other folks might know better.