You will probably get all kinds of answers. Check out the horses of the people who post, which might give you an idea of how the program recommeded is working.
There's more than one right way to feed a horse and some people that feed much differently than I do have horses I think look just as nice.
My program is simple as can be...
I feed complete senior pellets to all age groups and all use horses. I choose this because I like the digestability of senior complete feeds, and that it has added protein, fat and nutrients. I also like the fiber and the fact that complete feeds can be used in place of or to supplement hay.
My horses also get orchard grass hay or a very soft timothy hay from this one farm who does it how I like it for my minis. I am basically a nazi when it comes to the hay and won't feed anything but SOFT hay to minis. I think stemmy, coarse hays cause problems from a bloated look on up to impaction colic.
The show horses get ground flax seed as a supplement. Everyone is regularly dewormed and free access to minerals / salt.
Here the show horses get about 50% of their diet from complete pellets and the other 50% from hay. Adjusted up or down depending. Non-show horses get probably 25% from pellets and the oter 75% from hay.