I have 2 horses.
I feed a ration balancer to both, alfalfa pellets to 1, vitamin supplement to both, and a joint supplement to 1.
The ration balancer and alfalfa pellets each have a big tall plastic tub on wheels (I found them at a recycling center, they were storage boxes for rolled up poster displays). The supplements I get come in resealable bags or buckets and they stay in those on a rolling shelf thing (also found at the recycling center).
In this pic you can kind of see the tall grey bins and the rolling shelf thing: 0414141402.jpg