Probably goes without saying but plan a gutter and drainage, and definitely good footing and drainage with the footing right around there. You also want to plan how/if they are connected to the pasture. We have our stalls as run ins in what sounds like a similar situation. I would also suggest doing dutch doors.
Our stalls are cement (don't know the distance, but far underground) then different stuff (maybe gravel? don't remember I was little when we put the barn up) then lots of heavy sand. Mats over the sand. This works well, there's a little movement with the sand, and you need to have a good boundary at the opening of the stall door so the sand doesn't go outside The only big problem is RATS!!! They tunnel everywhere! This is an issue at a lot of places with any sort of tunnel-able floor, so I wouldn't say don't do sand, just something to be aware of. I would suggest putting in windows too depending on the building, and make sure you have a storage area for feed and anything else (tack, grooming supplies)
Thanks for the reply.
Yep, we have plans for gutters and drainage to go with it.
We checked the height and decided not to do the loft storage area, as it would be wasted wood.
We have hay storage on the other side, 30 ft away, so that is good, grain is in the actual barn, even close, so check there, also. :)
Footing, we were going to to it like our current stall (which would turn into storage)... it has heavily packed dirt and then conveyor mats over top of that, and we use straw as the bedding. My horse was stalled for a month 24/7 with only small hand walking after surgery in that stall and she did great. It had only the bottom door.
As for rodents... we have 4 very efficient barn cats for that- they have even
taken care of much of our burrowing animals, which is great for the horses in the pastures- not nearly as many deadly soft spots or holes.
It won't be a run in, as it actually isn't within the boundaries of any pasture. The horses have trees in all of their pastures which they use for cover. The stalls would be true stalls and only used infrequently. We recently had a big warm up and all the snow melted down our back hill and then refroze, causing everything to become unsafe for the horses. They were living in our front yard, which while they loved, wasn't ideal. :) It would have been nice to be able to have 2 stalls for them to go to (we have 2 horses, 1 stall currently).
Thank you very much for your reply, Yogiwick!