(From the Chicken Health Handbook/Gail Damerow/Storey's Series)- "use wide roosts constructed from 2×4 lumber with the wide surface facing upward, so feet are entirely covered by the body. Low ceilings or roosts close to the ceiling helps traps body heat. Humidity control is important, as humidity w/i a coop ie elevated due to damp litter, fresh droppings, and respiration. Fix leaky drinkers, block entry from rain/snow,keep the outside of doorways cleared of snow so it won’t get tracked inside. Deep litter that’s stirred or topped off frequently absorbs moisture from fresh droppings. Deep sand retains daytime heat to keep the coop somewhat warmer at night. Use dropping board and remove droppings frequently. Respiratory humidity is controlled only via proper ventilation. If condensation collects inside the windows,ventilation needs increased.