What are the best foods to feed a chihuahua?

Question
On March 18, I purchased a 7 week old male chihuahua. I tried feeding him Classic Entrees Gourmet food for dogs Beef Dinner but he wouldn't eat. I suspected he wouldn't because I bought it from Dollar General. I immediately called his breeder to see what kind of foods she was feeding him. She told me to feed him Purina Mighty Dog Classic Gourmet Dinner and try some cooked chicken cut in small pieces. I went to Wal-Mart and bought the Purina Mighty Dog Gourmet Dinner and Cesar Canine Cuisine Gourmet Filet In Sauce (Grilled Chicken Flavor). He would not eat the Purina or the Cesar. He manage to eat all the cooked chicken that day but wouldn't touch it the second day. Also,I tried giving him Dairy Fresh milk but he wouldn't drink it.
Please help I don't know what else to do? What brands do you suggest? If it is a more expensive brand please tell me where to purchase them.

Answer
Most puppies will happily eat anything they get, but some take a little while to adapt to their new home before they will eat.  The heavier they are, the less likely to eat.  There is very little good information about dog food available to the public and huge amounts of speculation and marketing hype.  As far as I know, the Mighty Dog the breeder was feeding is as good as anything.  I would cut out everything else.  cows' milk isn't good for puppies.  

Evaluate the dog as illustrated in this link, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx You may want the vet to confirm your judgment. Adjust the dogs food and exercise as needed to reach its ideal body condition.

The worst thing you can do is to bribe a dog with rich foods into eating more than it needs. Instead, Put down the dish with what the dog should eat, and give it 15 minutes to eat. Then take it up. Do not give it anything to eat until its next scheduled meal. In a few days, it should be eating what it needs. Continue to check its ribs and adjust the food as needed. A Chihuahua puppy doesn't need a lot of food.  A quarter cup 3 times a day may be enough.  

Likely the foods you are trying are mostly corn based.  Some light eaters do better on a more concentrated, meat based chow.  If you can't get him to eat enough of the Mighty Dog within a week, you might try one of them.  Iams and Purina 1 are god, and you can buy them at Wal-mart or a grocery store.  I haven't looked, but Dollar General may even have them.