My Haflinger can live off a flake of alfalfa a day...just saying. I can't get weight off her either. Been keeping her on a dry lot, exercising her four to five times weekly. Nothing medical. Just an extremely easy keeper.
P.S. She doesn't get any alfalfa. We live in Ohio. So grass hay is plentiful here. But she could live off 1 flake of it. She only got two flakes of grass hay a day over the winter.