I don't know if you're leaving it on all night or not, but that can really throw the girls off and lead to some unpleasant side effects. A timer makes all the difference for us here. Last year I tried fora while to plug it in at 4:00 every night myself and then unplug it before I went to bed. I forgot sometime, either to turn it on or off, or did them at different times. When we finally got it on a timer that comes on at 4:00 every evening and goes off at 11:00 at night, well, wow, what a difference!! I know a lot of people prefer to have the timer go off in the early am hrs, but we haven't have any problem with the light being on when they find their way into the coop at night.