Thanks to everyone for the info. My hen house and breeding pens are open on all 4 sides and set up to make the most of the shade and breezes (for those common summer days when the heat index is over a hundred). Not good with 40 mile an hour winds and in the 20\'s. I wrapped the whole thing in plastic and mixed sawdust with the cedar shavings that I keep in there all the time. My hens are like little tillers, constantly turning the dirt, manure, and all else. When the sawdust starts to compost, it gives off heat.
I think Paul is right about the change in weather being the biggest problem. And Mike\'s point about hardiness is very important. My hens haven\'t misssed a step, egg production has been the same and no sniffles.
With chickens, dogs, cats, and horses, there is always some \"small to others but huge to me\" concern to deal with. What my husband likes to call the latest episode in \"As the Barn Turns\"