I don't have a light out in my adult coop because I needed one for my chicks that are inside. The chicks are 4 weeks old. Do they still need the heat lamp? My house is about 70 degress downstairs where they are. It is getting cold at night and my pulleys don't have a insolated coop. Am I able to move the heat lamp outside? Will the chicks inside be fine? I have a heat pad I turn on for the chicks to lay on every night. That seems to keep them warm.