Mine gets saracens high fibre, alfa a oil, linseed, forage plus natural vit e, forage plus winter skin and hoof, yeasacc, and 50/50 hay/haylage mix. In the winter I've added beet pulp (for whatever reason they don't feed it in the summer at my yard). I did have him on some arthritis supplements but since pulling shoes he hasn't needed them. My vet is astounded at how well he looks (he's got dapples in November!). Mine has weight problems in that he thinks about exercise and loses weight (every human females dream). He is out of work apart from light walk work until he can grow all new feet but is doing better than he has ever done weight wise (even when out of work).
For my retired one it's a combination of Kwik beet, linseed, chaff, hay and he gets extra time on long grass while we still have some. I'll increase quantities if his weight drops off during winter but I like him to come out a bit slender so his feet are ok with spring grass.
He's on a herbal joint supplement with Bute as and when needed.