hello and welcome to yorkie talk!
i am so sorry to hear that you're here under these circumstances. so many yorkies and all breeds of dog have been getting terribly ill from chicken jerky treats. we have been seeing this over and over on this site so please definitely take that into consideration. waggin' train is made by purina and says made in the usa but on the back in fine letters it states that it is made in china. they are very deceiving. there are recipes on yorkie talk somewhere on how to make chicken jerky treats at home and it is very easy.
if the drs have not gotten a definite diagnosis, if this were my baby i would be taking her to a specialty clinic for a second opinion. preferably one that is 24 hours. here is a link to find a board certified specialist in your area.
ACVIM
please put a call in to the vet and ask if you could give her plain boiled chicken breast or anything else. you should definitely inform them that your baby will not eat the food and find out what is safe to give her. when my nika had pancreatitis she would not eat the prescription food either, so that's what my vet suggested along with karo syrup to keep her blood sugar from dropping. but you would need the vet to ok that for your situation...
please keep us posted on how your little one is doing and know that your baby will be in our thoughts and prayers!! again welcome to yorkie talk!!!!