^^ Agree.
Also, in my humble opinion, those are not very good foods and could very well be upsetting her stomach. Check out
Dog Food Analysis - Reviews of kibble -- I believe they're all rated 1/6 stars. I like this site even better
Dog Food Reviews | Dog Food Ratings because it explains all the ingredients and why they are good or bad. Nutro Natural Choice scares me, if you google "Nutro Consumer Affairs" you will read many bad things about that food! Also, over-feeding is often a cause of runny stool.
I used to be a believer in dog food is dog food... but after much research, I realize how much crap is actually in those foods! There's a lot of higher quality kibbles out there that won't break the bank. When you're feeding a better food, you also can feed less so you're probably spending the same or less. For reference, Jackson is 16lbs and eats 1/4 cup of Acana kibble in the AM and 1/4 cup in PM, making 1/2 cup total for the day. I've found a lot of picky dogs like Acana, Orijen, Taste of the Wild, Nature's Variety, Fromm, etc.
I wanted to wish you luck
I know what it's like to have a picky dog! lol