I need suggestions to help my friend make/build some sort of a better chicken coop before winter, because here in WI it get's pretty cold! Here's the situation: The chickens are currently roosting in the horse's lean to, but come winter it will get too cold in there for them. I suggested a large dog house (there's 13 chickens) with a heat lamp, but I'm afraid that would be too small. Any other suggestions? She would like to be able to close them in at night in the summer somehow also. Thanks in advance!