I love my double walled boxes. I stuck a Min/Max thermometer in one the other night when it got down to 18 here. With 2 cockerels in the box, and bubble wrap over the scat hole , the low temp was 45.No lights.I am very torn though about putting in a 40 w. bulb,because we are forecast for 10, and minus 1 with 35 MPH winds on Tues. We did put up 50 feet of clear , nylon reinforced tarps to the West today.They will let the sun in, if any,at least.........Would you believe that 3 more 5 month old pullets came into lay today ? Crazy girls.
Those boxes are a good idea for people up north. I liked them.