Hi & Welcome
...he has been having an ongoing abscessing in his front right hoof, so bad this past time, we thought founder, called vet out, she took xrays, coffen bone rotated a hair, abscess on top tip of coffen bone, but no founder, soft soles and very flat...changed farriers since then, he is doing much better then before.
I'm a hoof care practitioner, FYI. Coffin bone 'rotated' any degree away from the hoof capsule, &/or flat, thin soles says founder to me. Why did she think not? What did she call it?
There are a number of factors influencing soundness & hoof function. Diet & nutrition is a big one, as is *good* regular trimming. Exercise is another. The more the better. 24/7 turn out with company is a good start for this.
Feel free to send hoof pics for myself & other hoof 'boffins' to give more specific opinions on, if you like. Hoofrehab.com is one source of some great info on hoof care, function, rehab, etc.
Now this thing I have a question about is he is not eating as much hay as he used to, leaving a good bit, plus when I am mixing up his feed, it seem like alot! Then today, when I was cleaning stalls, I found he had left some of the min/vita in his bucket, this is something he hasn't done until today???? He drinks ALOT of water!
Splitting feeds into as many meals per day is best. Feeds which are too big or too infrequent can pass thru the small intestines into the hind gut without being digested, and cause issues, including laminitis. While horses need lots of reasonably low grade roughage - ie hay - if they are having bulky hard feeds, this will reduce the amount of hay they eat.
Re leaving supps, it could be that he instinctively 'knows' he's had adequate of those minerals, or it could be that he just doesn't like them & has sifted them from the feed. If you think he does need them, wet down the feed a bit more and perhaps add *a little* molasses to make it more palatable.
I can't comment on the amounts & specifics of what you're feeding, because you really need a proper analysis to work it out. It also depends on the area the hay/pasture is grown as to what nutrients will be in it. I use KER(Kentucky Equine Research) Gold pellets as supplimentary to pasture & I have found their nutritionists are happy to provide nutritional advice by email.