Adriana-
I had to switch to a different Pro Plan formula because after we switched my dogs food thinking it would be better for his allergies, he had a bad reaction (vomiting, diarherra) to it and after that the Sensitive Skin & Stomach no longer was working for him. After talking to a lady at the Purina vet diet customer service line for an hour we determined he might need a lower fiber food, so we went back to the Pro Plan Sport 26/16 and hes been perfect ever since.
Edit: As far as the expired foods go. The only time a store should be putting foods on sale are when they are CLOSE to expiration, within a month or so. If they are not checking their shelves regularly for expired product that is an individual store issue. PetSmart is known for having food be in poor conditions like this. You might be better off buying from chewy.com or seeing if any of your independently owned local pet stores will order the product for you or carry it in store. They will likely not have storage issues.
