I had my heat lamp all the way to the ceiling before my chicks got comfortable. At 3 weeks old they are in an empty coop at night. I still turn the lamp on about 10:00pm and off at 6:00am. Im not real sure they need it then. The are outside all day, but its very warm here during the day. This weekend they will be 4 weeks old. Im taking the lamp out of the coop. Let them get used to natural light cycles.