we have an 8 year old coton "Peyton" and she is the love of our life. Our vet recently suggested we switch her diet to a mature food. We went through the agonizing change over a 3 week period and she has taken to the new food in my opinion but my wife feels she hates it. She did up chuck dinner 5 minutes after eating....just once. We have used Nutru Source regular and now Mature. Any suggestions?