Enclosed horse pen?

I am looking for a cheap and relatively simple design for an enclosed horse pen ( like pictrured below). the pen is already exsisting and we just need to build a roof for it. the diameter is 29 feet and the roof will need to be able to support up to 3 feet of snow or be angled enough that snow can flow off.
Nmearly anything helps
Thanks, Zach

Picture of Enclosed horse pen?
Take a look at the sort of thing that "Shelter-systems" make
budhaztm (author)  steveastrouk6 years ago
i looked at those, pretty darn cool. one could just scale those designs up a bit. thanks