Just an update after a week or so . . .
I feed a full bale in the morning, a half bale in the afternoon, a full bale in the evening. This week we've been lucky with weather cold enough to leave the horses out in field so I've been spreading the hay out one or two flakes per pile over a large area. At each feeding there is generally just a touch of the last feeding left--which means they are getting what they want and not wasting too much.
2 1/2 bales seems about right for our horses. We have six, total, but one doesn't have any teeth left so he doesn't really eat much hay--maybe a few pounds per day. Which means the others are averaging close to 25 pounds per day which seems about right.
Bad news is that we probably don't have enough hay for the rest of the season. The good news is that we expected that when we got the sixth horse (a boarder) and knew we'd have to get another ton, at least. Maybe we'll just get two and not have to worry about it.
Tomorrow it's supposed to warm up and rain so we'll have to stop putting the horses out. Rats. They do too much damage to the pasture when it's muddy. Hopefully, they'll play nice at meal time and I can just put the hay in the feeder. Before we tried free choice we had to make separate piles for each horse plus one extra. We'll see how it goes!
"Don't just feed it! Ride it!" And the People said "AMEN!"