I would agree. Do you have a thermometer in your coop? I have a heat source in my coop right now just to keep the temps in the teens, since we have had subzero temps at night here this week. Many people don’t use heat at all unless it gets 20 below, but I take the chance. It is a personal choice for me, and any heat source can cause a fire. If you do bring him inside to a warmer spot, try to keep him in a cool spot, so that he won’t have such a drastic change when he goes back outside. I would put him back out immediately in the mornings, so that he can tolerate the cold.