By Kathy:I would like to encourage people to feed hay by weight. Get a little infant scale and weigh your hay each time you feed. I buy hay from the same grower every year and I can tell you that every single bale is a bit different in weight, even from the same cutting.
If I'm feeding 7 lbs of hay at a feed, then sometimes that's one flake and sometimes it's one and a half depending on the bale. Just when I think I can eyeball 7 lbs of hay I'll pick up what I think it is, weigh it and find that I can be off by as much as 2-3 pounds. Right now I'm feeding the horse at my place 8 lbs of grass hay per feed and she's fed twice a day. Another mare will get fat on that, so that one usually gets about 6 1/2 - 7 lbs per feed. And then you have to factor in whether the horse is working or idle and adjust the amount according to that, or the time of year (snow, cold, rain, etc.). Hope this helps. Kathy