At 15, she is very unresponsive to change. We have tried Z/D by Hills and she will not eat it, as I understand it has hydrolyzed chicken. She will eat the milk bone treats of Z/D. She has lost 7 pounds and is now 23 pounds. I am looking for sources of protein to try and how or why they will work. I can provide any info you need, but please I am looking for your expert suggestions of proteins that I can try.