First off! Thank you from Gracie and us for the wonderful Secret Santa gifts. Please check out the video of Gracie opening her gifts. It was manic. She LOVES the wubba. It has become her favorite thing to play with since opening it.
Now to the food issues. It's likely something in the food she's on that is the culprit. We have discovered through trial and error that HRH is likely allergic to Chicken and Salmon. We feed her the Fromm Beef Frittata and a lot of issues similar to what you mention Katie has have cleared up with the change to that food about a year ago. What issues she has had we attribute to still trying to find just the perfect treat. We have tried several different types and nothing has been exactly perfect yet. Fromm doesn't have a treat that is chicken, salmon and grain free.
All that said, they do have allergy testing that could tell you exactly what to avoid.
Or, as many of us have you can try a slow transition to limited ingredient type foods and watch the results. No one food seems to be the perfect solution for all bullies. we all seem to have to go by trial and error. It can be a long process depending on just what your girl is sensitive to.