Well, I think, one shouldn't dramatize the whole matter.
In over 40 years of horse ownership I only had 2 colics. One due to stress, the other of unknown causes.
Putting hay on the ground is no problem (horses eat from the ground!!), it depends where you put it and if they eat i.e., due to hunger, old hay with mold.
Feeding a horse ALWAYS off the ground, say in shoulder height, causes lots of other problems as the last century has shown. Poll, withers, and back are then in an abnormal posture and over the years issues will develop.
Dry spots for hay (best in a round feeder if fed on pasture), cleaned from moldy hay and wet 2 day old left overs are a good choice.
Grain in an unbreakable and easy to clean feed bin indoors or under a roof outdoors will prevent further problems.
If horses are fed three/four times a day, otherwise healthy, a good selecetion of roughage provided, they most unlikely become colic. I lived in sandy areas, too. Common sense and knowledge prevents a lot
Stressy horses need to be treated for that cause, then colic will not become an issue that easy, my experience showed.