Open-air coops

Do any of you have experience with open air coops? I've got a very simple hoop-coop covered by a few tarps, and have been wondering how well or poorly it'll work during the winter. I'm encouraged by some pictures of an open-air coop in Harvey Ussery's book, and by what I've read in this book I stumbled across the other day.

I'm in the Ozarks, and we haven't had a lot of cold yet. The coldest it's gotten here so far is about 18 degrees F or so, and just for one night. I can at least say that so far no frostbite, the chickens are all acting normal and happy, and I'm still getting eggs. (Granted, I've only been getting eggs for about a week in the first place) The book below makes claims of chickens doing well at temps as low as -40 in open-air coops! Especially if you're relying on electronet for predator protection, this could seriously simplify coop design and construction.

http://books.google.com/books?id=o08PAAAAYAAJ&printsec=frontcover&dq=inauthor:%22Prince+Tannat+Woods%22&hl=en&sa=X&ei=eWjLUJ6iMZOi8gS9kYG4DQ&ved=0CD4Q6AEwAg#v=onepage&q&f=false

It is not cold so much as wind and rain they need to be protected from, so they need a roof and some kind of wind blocking material or small structure they can huddle in. But my experience is in a warm climate, Zone 8. Also, some breeds of chickens are more cold hardy than others. Heavy breeds with rose combs or other small type combs are more cold hardy than light breeds with large combs, who may do better in hot weather.

Imagine birds in the wild who huddle in trees next to the trunk, they don't endure cold in the open at night, they find shelter out of the wind and rain.

That book is by Prince T. Woods.

It is a classic. If one follows his designs (length/width proportions are important), and orients the coop properly, they will keep chickens warm enough, and much healthier than in conventional 'air tight' coops.

Proper ventilation is much more important to chicken's health than warmth.
My grandmother kept chickens in an open sided (south) coop in Churchill, alongside Hudson's Bay. Minus 40 was not uncommon there.
Polar bears were more of an issue than temperature.

I have kept chickens in open coops, but I have never raised them in a cold climate.
The egg farm where I worked in South America had hen houses that were a series of posts to support the roof...no sides at all.
(They would put up chicken wire walls merely to direct the hens to the proper yard for the season.)

Thanks for the replies. It makes me worry a bit less about my own set up, though I'll keep a close eye during the cooler periods for certain.

Wow, I can only imagine having polar bears as the main chicken trouble! I wonder if an electric fence would be enough to keep them out?

Yeah. Churchill's nickname is"Polar bear capital of the world".

From everything I know about polar bears, I doubt electric fencing would slow them down when they're hungry.
I think the fear was more about themselves than the chickens.
A dozen chickens would merely whet their appetite. A couple humans would hold them over till they found a 400# seal.

A friend of mine who studied polar bears for several decades put it simply:
"If you meet a polar bear on his turf, be prepared that either he, or you, is going to die."

I'm using a hoop coop this winter and am completely satisfied with its performance in keeping out the elements. I've got ventilation open on all levels, more at the ground and good venting at the roof line. I've also got two sides covered in clear plastic to let in the southern exposure to winter sunlight. I'm loving this open air coop!