I, too, feed round bales.
Here in NC, I have several suppliers - one of whom will deliver them up to 5 at a time for me. I put them directly out in the pastures (have 2 pastures and 3 paddocks).
The pasture that has 8 boys in it - 1 round weighing roughly 800 lbs (guessing - much smaller than they were when they were 1,000 lbs) will last a week. The pasture that has 3 full grown Arabs in it will get a little over a week per round (has the most grass and they are grazing a lot right now and only getting fed 1x daily and FAT). Have only 2 ponies in one paddock that gets a round - wish I hadn't put that one there! Should have stayed with using small squares and individual feeding in that pen! The other two pastures vary as to how many bales are consumed per week/month. Number of ponies has gone up and down recently in both. Neither really has any grass - enough to hold down both the clay and the sand and "look pretty". They are "mowing" it as fast as it comes up!
The hay is out 24/7. Some bales get a round cattle feeder around it, some get tipped on end and get a 16' cattle/stock panel wrapped around it. When I use the panel, I can tarp the hay (haven't tried with the other bale feeders - but don't think it would work as well. Both help with waste a bunch, but don't completely prevent it - as they can pull the hay out and still stand on it and use it for bedding. I used to pick up all the loose hay and get it back into the feeder, but again found it didn't always matter and really haven't had time to do that lately... I handled more than 300 small squares last year and YUCK. If I don't have to move and stack it myself any time soon again, I'd prefer that. I picked up 70 bales from a field and loaded about 1/2 of it myself into our stock trailer - then got it home and had to unload and stack it by myself - thankfully it didn't rain as I wasn't able to do it all in one day - thought I was dying by the 3rd,
Recently no one I have contacts thru has the small squares and half the hay fields in our area are either growing wild or have been torched to see if they can get another growth since they couldn't get into flooded areas to cut...
I did get some hay tested last year (whew -were some folks MAD about that) but it was interesting as I found our drought ridden areas were getting really pretty but really "crappy" hay (how is that possible???). It explained a lot as to how our ponies have been looking and this year with the abundance of rain and oversaturation - we're still having major problems with hay quality. My feeding program has tripled in the last month or so and still have a couple that are loosing or have lost too much weight. I've moved several ponies and one aged arab into the only completely grassed field we've got (not usually having ponies on it) - and feeding them 3 x daily - looking at going to a 4th feeding!
MAN, do I miss that Canadian and Montana hay we used to get!! Wish I could afford to ship a couple semi loads down, but I can't...