I have had my heat lamp off since the end of spring, when my birds were 12 weeks. It was in the 60's at night and it was time. Since then my birds have never entered the coop. My run is fenced in. the birds free range all day then go back in the run at night. The run has a roof over it and the birds love the framework as their night time roost. Today it snowed. I turned the heat lamp on and who would have thought that the birds all stayed in the coop. They wander out when I leave the house but all seem to go back in to the heat zone. I am now thinking of a heated piece of PVC like the one on youtube.