[Ellie May]

While I don't normally tell people not to listen to their vets, please be careful. I would not follow that advice.

In my opinion, Yorkies should be fed at least twice a day and preferrably more. They shouldn't be expected to store sugar for this long and be able to function.

I would not feed Bil-Jac. There are better foods out there.

And if the food is complete and balanced for adults, you aren't going to do much by switching foods as far as giving the everything they need. Theoretically, if a food is AAFCO approved, they are getting what they need. You may need to feed the older one a senior food and pups need pup food but adults would be fine on the same food for an extended period of time unless you are concerned about acquired allergies.