Diamond is a poor food. Please take a look at this website. It only got 2 out of 5 stars.
Diamond Dry Dog Food | Review and Rating
however, if you are feeding Diamond Natural, it got a better four stars.
Diamond Naturals Dog Food | Review and Rating
Take a look at the 5 star only foods.
Five Star Dog Foods
If you are visiting relatives and the petsmart is nearby, no doubt there is a Petco nearby too. Petco has far superior quality foods than petsmart. many petco's have redone their food section to have holistic and oragnic foods now. Also check out this thread to get free samples of super premium food.
http://www.yorkietalk.com/forums/yorkie-health-diet/76518-super-premium-pet-foods-list-ask-free-samples.html Aviod foods that have meat by products, corn, wheat or soy in them, and especially avoid them if they are in the first five ingredients!