So we bought some fiberglass batting to use in the coop. Our winters are very cold, -30°C to -40°C. This was the cheapest, most efficient way to go. We are painting the exterior wall with weather resistant paint, and the coop will be raised (on skids... 4" high). The floor is 3/4" plywood. All ventilation is closable and covered with 1/4" hardware cloth. The interior (second) wall used to conceal the fiberglass batting will be painted with weather proof white paint, and covered all the way up- And the roof insulation will be covered, too. What else can we do to further preserve it!?