I've found the saying, "men plan, G-d laughs" to be true for both my child and my dogs. So what you WANT to feed them, you may find does not agree with them.
My latest gift from the heavens above, my 7 month old cocker... he has a very excitable bowel. Let's just call it that. When he was 3 months old we went through 6 long weeks of explosive fire hose diarrhea with no known cause, I spent well over a thousand at the vet's office taking him in every week having his poop tested for parasites and his blood checked... we never found anything wrong with him. He had to eat cottage cheese and rice to not be a fire hose, poor thing. And I kept trying dog food after dog food, trying to find the right sensitive stomach one that would agree with him. We finally settled on Science Diet's sensitive stomach one, luckily my other cocker does well with it too. Is that one better than the others? I doubt it, that one just happened to be the one that finally agreed with HIM. What works for other people's dogs might not be the best for yours, I'd ask your vet what they recommend and read the ingredients on the bags at the store. Good luck and hope you have many happy, healthy years together!