I also have had a surge of mild colic-like symptoms through the barn. I highly doubt that it is sand colic since three different horses have had it and none of them have much sand content in their manure. It starts them laying down, getting lethargic and not wanting to eat anything but grass. Then they spike a fever. I give them banamine and cold hose them to bring down the fever and then they are fine. I'm not sure what is going on and the vet keeps telling me its just colic. They aren't thrashing, biting at their sides, still have gut sounds and pass manure and urine. Two of them have had a tenderness right by the flank, but underneath.
If you have heard of anything, please help :( I'm getting really desperate.
I live in South Florida, if it helps.