I just got a rescue yorkie - 5 years old. She weighs 5 lbs but should weigh 8-10lbs (according to the vet). My vet told me to put her on puppy food since it is a lot higher in fat content and we should see some weight gain in a short period. I think because of the high fat content, it's probably tastier to a dog and a finicky eater should be ok with it.
Jasmine will eat it, but I do have to stand in the kitchen with her to make sure she stays focused on eating and not get distracted. (Plus Millie (my other yorkie) wants to eat the puppy food too)
Of course because he is a vet he recommended Science Diet Puppy small bites. I took the bag (it was free)
. But once I am done with it, I will see about Merricks puppy food, since Millie eats a combination of the Grammy's potpie and Wilderness Blend.
My vet wants her to eat about 1 1/2 cups a day. Jassy simply will not eat that much. But I think I get about 3/4 of food in her a day.