Here is the review of the Diamond Natural Chicken and Rice. It is not recommend by Dog Food Analysis:
Dog Food Reviews - Diamond Naturals Small Breed Adult Chicken & Rice Formula - Powered by ReviewPost
The Diamond Natural Puppy food is 32 percent protein and I feel that is too high for a yorkie puppy.
I have been feeding Canidae and Chicken Soup for years and have never had any problems. Both are produced at Diamond Manufacturing. Just as someone else stated there are many problems that can arise in producing dog food as well as in people foods. With any dog food you will find people that have had bad experiences. Another thing is that I don't necessarily believe ever bad review I see. After the dog food recall the sales for Canidae skyrocketed and it would not put it past some of their competition to put out some bad review just to hurt Canidae's business.
When anyone switches their dogs from one dog food to another they often, in the beginning, they may get poor results, like loose stools. Dog's that have been fed primarily a grain based dog food will need more time to adjust to a dog food that has less grain and higher quality protein. From my own experience of raising yorkies for 12 years I have discovered several years ago that mine do not do well on any dog food with beef in it. I primarily stick with chicken or lamb as the first ingredient. Although, mine do love the Fromm Duck and Sweet Potato but I give that more as a treat. I just mix in a little with their Canidae. My Yorkies also don't care for dog foods that have a lot of fish in them.
I know many dogs do well on dog foods that have lots of grain in them but in the long run I feel that their health is compromised. With a quality dog food you get a lot less waste coming out than you do with those dog foods with lots of grains and fillers.