I checked climate zones for Alabama and you are in zone 7a in the northern and down to 9a for the lowest area of the state. My area of NC fluctuates from 7b to 8 as well. We do occasionally get snow, more ice though. melts off fairly quickly. Our coops are simply hooped cattle panels w/ combinations of chicken wire (replacing), 2x4" wire & hardware cloth with tarps for roofs. Open air, though I do have parts blocked at the bottom for wind & rain, mostly open. No issues with frost bite. Yes, after some of the last four hurricanes, we've had to replace some of the tarps, but not all. Had more work to do with the tin roofs on some older outbuildings that were damaged and ripped off. Even the tarped roofs get hot during mid summer & the birds really appreciate any breezes that go through.
I had completely forgotten about a foundation. Yes, wood works as do cement blocks or even poured cement (prob hardest & most expensive?).
There is a way to make papercrete blocks that will work, too. I am working on that for ours (I have 3 - 8x8 hooped coops <meant to be tractors, too heavy for me to move, now in permanent spots> in our pony pasture that will need to have a foundation set under them now as the treated wood frames rot away AND a series of wood built square pens that were here on our property when we moved. Still need to get the last 3.5' pen hooped as well. We are digging down below these to add blocks to prevent the digging critters from getting in.) - great way to use up shredded paper & shredded plastic mixed with cement & water to get a solid, but lighter weight than straight cement blocks. You would have to make your forms. You can drill through papercrete or set rods for bolting to.
Our first batch had too much paper/water and not enough cement. We also used Quikrete instead of Portland cement (recommended in the papercrete articles, quickrete is used for garden blocks with no paper shreds in articles are found). The blocks were somewhat soft when they cured, giving when we walked on them and the one broke with my weight. We'll make some more, the mix isn't exact for the small batches I'm making up at one time.
