I don't have the same type of soil (I live in black dirt farm country) but we have monsoon type springs sometimes. After winter thaw and tons of rain, we get mud for sure. My lean to in one of the pastures is on a bit lower ground and it can get deep. We re-do footing every few years as it settles. We take the loader and get all of the mush off the top and then dig down a few feet and fill with stone and then backfill with sand over the top. We also do about 20 ft out in front of it as well. As far as the sand & colic, you can use raised hay feeders to eliminate the possibility.
Life is like a camera. Focus on what's important, Capture the good times, Develop from the negatives and if things don't work out, Take another shot.