We have two lights in our coop (its large, 10x16). One is on a pull chain to use when we need/want light to do something in the coop. The second is on a timer. It comes on around dusk and off after the coop door closes. We adjust the time as the sun adjusts throughout the year. We have Guineas who do not like to enter a dark buildimg so this gets them in (most of the time) before the door closes.