A horse at my barn foundered. He's not overweight, overridden, not on lush grass , diet is mostly hay and not much grain. Gets a trim every 6 weeks. Nothing has changed in his care . Are there other reasons why a horse founders? The vet said 8% on one foot and 15% on the other. The farrier said he's coming on Monday. I thought founder was something you want to get treatment on asap?