Hi Lacey-
I kind of hate to complicate things given the title of your post, but your 13 week old giant breed has very specific dietary needs while he is growing that differ greatly from your 16 year old Chihuahua.
Large and giant dogs that will mature to over 50lbs are at high risk for bone growth disorders due not only to genetics, but improper nutrition during growth. Large breed puppies have difficulty absorbing calcium correctly. They require a food that has a controlled level of calcium to help them grow slowly. Most of the time a food labeled for “large breed puppies” will meet those requirements…sometimes they do not. Diamond Naturals does have a large breed puppy formula that is All Life Stages, so your Chihuahua could eat it, however some small dogs are sensitive to kibble size so you would have to get a bag and test it out.
Homecooking is not a bad idea, however the diets have to be properly balanced and when adding the challenge of owning a giant breed puppy, many will advise that a commercial diet that meets AAFCO should be fed during growth to make sure the dog is recieving proper nutrition. When your giant breed pup reaches adulthood you could begin researching homecooked meals. BalanceIt.com is a good place to start.
