Well first off i'd try going grain free, most of these replace grains with potato (Grains are likely the cause). If shes still having trouble it may be the meat, it may be the potato...One of our dogs has a very sensitive stomach, on certain foods she'll barf it up. She's been on the Nutro Venison for Sensitive Stomachs (she likes it and tolerates it well) but there is A LOT of rice and grain in this food and I want to switch here to something better.
Eagle Pack and Wellness are available to me, out of these brands which dry would you recommend?
If its the meat then an alternative would be Solid Gold Barking at the moon which uses mostly fish and only some mammal meat, and instead of grains, potato is used. Fish is usually more tolerable.
If its the potato causing problems, natures variety food called "Instinct" sells grain free which uses tapioca instead of grains or potato, which has been shown to be the most hypoallergenic grain replacement for dogs, bar none. 90% of the protein is from the meat in this food as well.
Never had any experience with eagle pack, but wellness "CORE" is grain free which you could try.