I got the same thing.
I feed puppy chow - the cheapest food that 'agrees with' her system. I started off with the best of the best - and then I realized that she eats a BUNCH of stupid stuff, so the bits of 'oh noes bad ingredients' in the cheap foods, are probably not hurting her any. I mean, how is 'chicken by product' so bad when she scarfs down chicken poop and dead things every day anyway?
My biggest reason for going with cheap food is the price. However, I would suck it up and feed expensive, if it actually seemed to make a difference in her health. But it doesn't.