I see you're from Colorado. Your weather parallels mine here in Canada in many ways.
With that in mind I thought you might like to toss these pix in the mix while you're
making your goat house plans. This is a converted grain shed that I painted and insulated to house my 3 ladies.
I left lots of ventilation on the east and west ends as they are the prevailing winds here and it keeps the air inside fresh.
I chose to use wood chips on the floor and, so far, that has worked well.
I built a small annex in order to divert the wind so that they can avoid any nasty drafts.
I have a small sliding door on the inside that I can close if I choose at night in order to keep warmth in and predators out.
I left some room on the inside to allow for bale storage as well as a pitchfork, rake and stuff.
I also put a window into the south side to encourage ambient heat during the cold winter months.
I only use the indoor feeder on the most cold of days, when it is just too bitter for them to venture out.
So far, there's not been a lick of trouble. Most days I use their outdoor feeder.
Good luck and welcome to TGS. Make sure to post lots o' pictures!