She pooped so much because of the food. I think of Puppy Chow like McDonalds, and Nutro like a homecooked square meal. Look at the ingredients. Puppy Chow is filled with fillers and by-products. Nutro has no byproducts and it takes a while (if ver ) to get to corn, and then they don't have the whole corn (which is hard to digest)

I swear, feeding her 2 cups of Nutro is a HUGE difference than the same 2 cups of Puppy Chow. They eat less, poop less, and get much better nutrition on a better food.

I am willing to bet her poop also smells pretty bad and is kinda squishy. The Nutro will also give less stinky poo and much firmer consistency.

PS: Get a new vet. Didn't they tell you about Puppy Chow? Didn't they go over Nutrition? From the photos, she is NOT in breed standard weight.