Today we have been having wind chill at about +9 & sun is out and so are my birds...I have noticed that coop temp is over 10 degrees warmer than the outside temp at 7AM every morning and that is with only 4 birds... Coop is 3' x 4' x 4' tall the run is totally covered with plastic and I have straw around the outside of all...the weather has not effected my silkies one bit they are still taking dirt baths in their favorite shady spot and ranging all over the place...have started corn scratch don't know how much is too much though... They get some in AM and again just before roosting...