Thank you both for your excellent replies! I feed Suzi By Nature. It does have a puppy kibble that she use to eat 

 I am planning on switching the new pup over gradually after a week . I also feed Suzi the canned version too, and it is rated a 6 on the list ! Shih tzu's are prone to weight gain, so I will have to be careful with my new wee one. The canned is very high in protein, so I am thinking it still can be good for my new baby at least one feeding. 
 My new pup is going to be bigger then Suzi as she grows. but, I guess that is ok! Shih Tzu's are so sweet and good natured . I am hoping those two will be the best of friends !  Suzi is young , and she is a super loving little Yorkie towards people. However, she is timid around dogs! We have a neighbor Chi, who is very tiny, about 3lbs, who bully's my girl! All this dog has to do is yap, and Suzi is so scared! 
  If Suzi is allowed to meet anther dog on mutal grounds she is fine .She likes a standard sized mini Snouzer pretty well. This dog is huge compared to her! 
 
 
 Suzi has always been the center of attention though! I just do not know how she is going to take it with a little fur ball coming home on her pad! i know that I have plenty of love to give both dogs!