Feeding Round Rolls in Florida

We have a herd of 3 horses, and are wanting to start feeding round rolls to cut down on our hay bill (especially right now in the dead of winter). My question, though, is how do I go about doing this? I'm in Jacksonville and get dew 2-3 nights a week this time of year, and daily in the summer. Plus, from May/June-August we get daily rain. How can I cover it or protect it from the moisture? (not to mention our humidity)

Either feed the hay under a shed or in a covered rd bale feeder like this one.

O`Neill Bale Feeder - Covered Feeder ONLY

Personally, feeding under a shed is the way to go as you get much more protection.