I'd try the alfalfa pellets anyway. They'll give her good protein, which helps building muscle, give more calories than grass hay (900 vs 1100 calories), you can hide all kinds of stuff in it, gets water in her, make her eat slow and are low in sugar(11%).
And she thinks she really gets a huge serving
Start with a handful and work up to the full ration. They soak in 15 minutes with warm water, a couple of hours with cold water. As long as it's cool, you can soak morning for dinner, when it's hot out, it's better they soak only a short time, they ferment.