Thanks for understanding. We still have ten horses but the barn is strangly silent when we go out in the morning to tend to them. The worst part is seeing that empty stall. Don't mean to upset anyone.
My wife and I mixed doctor appointments with shopping and going for lunch today so we had the first chance to sit down and talk about what we may have done wrong. While most of our hay is clean, on occasion we may find some mold but neither of us felt that was the cause. We are supper careful to smell our hay as we break a bale open and peel off the flakes.
We had spent the day before Jett collicked leveling his dirt stall floor and compacting it then laying down rubber mats (used so there was no smell). We spread wood pellets over his usual "wet spot" then spread out about a bag and a half of shavings.
I noticed him sampling the shavings when I let him back in. I had not thought anything of it because horses will often take a bite or two of fresh bedding. It was early so I did not yet offer evening hay.
My wife then remembered that a goodly amount of those shavings were gone the next day when she found him down. Apparently, he must have pigged out for whatever reason as the shavings were nothing new for him. I had not noticed anything when I hayed him the evening that we had worked on his stall. That is the only thing we can figure out.