Was glad to hear you went grain free, I realize some dogs tolerate more digestable grains like oatmeal and rice but there are so many who do not. I would also feed a singe protein source at a time so you can rule out a possible protein allergy as was suggested like turkey or lamb. Pumpkin puréed is so good for a rumbly tummy. It can really take about four weeks to know how a food is or is not working for your dog though- a week of transition blending, a week or so to process that all out and a week or so to really respond to the new input. Don't forget that treats count too! Be dilligent about checking your labels. Probiotics are great, you ca buy a powder form to sprinkle on what she will eat or maybe she will like plain yogurt. Many foods include them these days but you might want some extra support. Glad you ruled out a medical concern
best of luck