Here's a few pics of our carport barn.
We got the carport, then enclosed the back (with two windows in back) and partially enclosed the front to have an open doorway (we plan to put doors on it before this winter, though, cause we have calves, now.)
The back 1/3 of it is a stall where we keep the freezer with the feed in it, and about 50 square bales of hay.
The part off the back is our addition of a corral with three calf stalls, and there is another corral off the right side with a calf "hut" in it (hut is about 6x6).
I don't have good pics inside, but you are able to see the gate to the one large stall inside on one or two of these.
This one is an 18x21 - but if I had known I would be putting so many animals on the farm, I would have gone larger. (hence the added buildings in the long line of corrals and barns
)
eta - as a chicken coop - well, I've considered it. The carports you can get are reasonably priced and sturdy (and waterproof - no leaky roofs from homemade jobs).
main issue will be ventilation - make sure you work on that when building it - because it gets hot and stuffy in the barn. The darker metal also absorbs more heat than a white one would, I think. Even with the heat, though, it is cooler inside than out in the summer.
Maybe you can get one or two roof vents to open or close when it is really hot in summer, and install those. I have one I picked up at a yard sale, have not installed it yet. It's one of those round spinny ones (like a fan in a bubble cage - looks like a metal hot air balloon).
I can't recall exactly what we paid for ours, but I think the main framing (we only had roof and sides, no ends) was around $1200.
the metal for the ends we got used corrugated stuff for a buck a sheet, and the wood is all treated if it is outside wood, the stuff inside to strengthen the walls (donkeys and cows like to hit the walls with various body parts
) is non-treated (cheaper).
meri