I fed my puppy Nutro (puppy formula) and it didn't do her any good. She rarely ate it and I think it was that food that gave her diarrhea. I went to the vet the next day because she had symptoms of hypoglycemia again and asked my vet if Nutro was good. She said, 'No. The brand name foods like Pedigree, Eukanuba, and Science Diet have more money put into it to make it very suitable for dogs.'
So I went to the store and bought Pedigree wet food for puppies. I let my pup smell it and she started eating a lot of it(which she needs to since she is soo tiny! 1.4 pounds to be exact)! She likes that waaaaaaay better than the Nutro wet food for pups. Plus, her poo is getting harder! I'm happy with Pedigree.
How old is your Chi? Mine right now is only 9 weeks. But even when she does get bigger and older, I'd still stick with the well known brand names. But of course, that's just me. I thought I'd just put my two cents in.
I feed my dog Nutro Natural Choice Ultra for puppies and I think she has done very well on it. Now the regular Nutro foods I wouldn't even think about buying, but the Ultra I like. The only thing I wish I could change is that it makes their stools soft and kinda stinkier than average but my girl goes potty outside so it's okay with me. I did a lot of research on dog foods before I bought it and decided to go with it. It doesn't have any by-products, chemical preservatives, and all that fun stuff. I also asked my vet about dog foods and he told me Pedigree, Iams, Science Diet, etc. but from what I have learned and read about those foods, they really aren't all the great lol. Now when I am done with this bag of puppy food I will be switching her to adult food. I will probably feed her either Royal Canin Chihuahua blend or Natural Balance. There are a lot of threads on different types of dog foods, so you might want to try to do a search of the forum. Also, there's a ton of info on dog food and information about ingredients if you do a search for it.
I think that everyones Chi's react a little differently to everything. That's why I shop at Petsmart. I first bought Petsmarts own dog food Authority because I heard it was a really good brand from a lot of people. But Seiah's fur got really dull and looked almost gray than black. But I recently just switched to Royal Canin, and i can see his fur getting a lot better. With the whole thing about liking Petsmart is that you can return anything and they'll take it back. I brought Authority back half empty and they still gave me a refund.