Quote Originally Posted by mike001
Buttercup, I think you're talking about black walnut tree shavings, yes it is very poisonous to horses.

Sorry horse lover, I forgot to mention maybe the teeth needed floating. Whoever thought of it, thanks, just don't remember who it was now.
But if that horse isn't dumping it sounds intestinal.
Ya that's it. They were breathing it in and then it affected some of their hooves from standing on it so long it got absorbed into them.