I have wasted a lot of hay before if they soil it or dont eat and it gets mushed in. Ideally a hay net tied up somewhere on a post/field shelter. But I usually do throw it on the floor and monitor if its wasted or not ie they must be having too much.
I have often thought about getting one of those cattle rings to fill up to stop waste or a hay bar?.
If I have done the hay nets in field shelter I fill up a whole load of them to last a few days to save time in the dark and I do work as well!
These: (and I am feeding hay NOW!) 4 posts about 6' apart, re-cycled cedar fence rails, cost = few cents for nails and fuel for the chain saw, only downside is that they aren't mobile but we don't get much mud anyway, the foals use them as nests!