We live in Seattle where the temperatures have been cool. ( 65 if we are lucky during the day.... low 50's at night) I have 7 chicks living ( all about 4-5 weeks old- mostly feathered) in the coop part of our chicken house and run. Yesterday was their first playdate outside. I have had a heat lamp on them at various degrees of height since week one. The temperature in the coop this morning read 63 degrees on the perimeter of the heat lamp radius. I'm sure it was warmer directly underneath. Are these gals old enough to just turn the lamp off? During the day? at Night? Always? Thanks.