I am in the same boat. Since I have adopted Alphie he was a abused yorkie he is 3-yrs old and is skinny to ME. Doctor says he is o.k. But I have tried all kinds of foods and have found "Natural Balance" and some vegtables(when he will eat them) and the "natural balance" stick seems to work He will gobble it down.
Don't know if he has really gained weight but his bones are not showing as much.
Cheryl