Good luck with your mare, colic is scary.

Lmo- What bedding was your horse on? I've seen horses stalled for long periods of time eat shavings or straw from boredom.

At the old barn, we had 24/7 big pasture, unblanketed. There was at least one surgery per year, many other colics. One horse had 3 surgeries, two more had 2. I didn't own a horse when I was there, so I didn't pay much attention, but the grain and hay were high quality, the only thing I noticed was that the water troughs didn't get scrubbed out much and were gross. The colics were at all times of year, mostly TBs, but a pony now and then. They had people out testing the soil and walking the pastures and there was nothing.