[gemy]

If the vet did not mention and over/under weight issues, at this point in time you might not have any.

I am not a fan of free feeding, as I do want to know what and how much each dog eats. I would transition them to eat from their own bowls. You can feed them in their crates, or in separate areas of the kitchen. The activity level differences would seem to indicate that over time if each dog is eating the same amount, a weight gain for the more inactive dog is likely. Also if you have not spayed/neutered yet, this can have repercussions on weight. It is not uncommon for dogs to experience weight gain after de-sexing.

As far as food goes there are lots of threads in the Yorkie Health and Diet forum for you to peruse.