Much prefer to distribute (roll out, bale processor) hay to the cows. In cold climates like ours, the feeders do freeze down, the cows do waste some hay, the manure and hay is really hard to get loaded up and hauled out and it is just more pleasing to see that long string of cows lined up at their "table". Gives a good opportunity to count, inspect and watch the cows better. Plus it is easier for the cows to haul manure than it is for me to do it. I use some feeders for the calves, but I generally hate them. I guess they are a "sin of necessity".
I would not let the feeders be empty if the space is limited. I hate to see those cows belly butting trying to get a spot around the feeder.
On a side note. I just bought some new feeders (cheap, farm store type) for my weaned calves this fall. I had a calf get inside one, As I approached to try to lift the ring off of it, she decided to jump through. Then she became hip locked and was running around the lot with a bale feeder around her waist! Finally went to get the portable grinder to cut a bar out of the one day old feeder

At the sound of the grinder, she had the sense to back up and get unhooked. I was able to lift the feeder off of her. Close call.