We only fed our boy Senior Extruded feed=he was on 1/2 cup of flax, 2 lbs Senior pellets, 2 lbs of soaked alfalfa cubes, 2 lbs of soaked beet pulp--he got this morning and night. He also had free choice timothy hay with only a marginal amount of alfalfa in it. We had no problems with this regime=of course it was started slowly and in small quantities as he body adjusted to the changes. He did so well with this it was remarkable---he was nice and chubby when all was said and done.
Good luck with your girl!!