I wish mine had more covered depth, the roost bar is over a shelf, covered on three sides, but a depth of just 3 feet, and that is the east side.
I found it used when lumber was super expensive and at the time we had ducks for six months over summer but now this is me outfitting it for a few laying hens my friend is giving me. I did cover the open area under the shelf previously as that did give the ducks some cover out of the wind if needed but I didn’t have them during winter.
I’m nervous about the cold (my chicken friend thinks I need to wrap the whole coop?) but we really don’t know how to do winter down here. In the freeze we had last Feb- lost powers for 5 days- people were putting chickens in their houses inside camping tents. It did get down in the teens but that’s not typical here.
You could tarp the two sides, leaving the gable triangle and the entire front open. That would give you more wind protection while allowing plenty of airflow for those January days that break 80F (we get those days here in North Carolina so I presume you get them in Texas).
I wouldn't use clear plastic on any part that gets the sun though because of the green house effect.
