Good catch Deuce! Definitely want them to identify.
About the food. The first yorkie I got was from an owner not the original breeder. The owner had always hand fed her baked chicken & rice. I started out doing the same and it is something almost every dog will eat. But I gradually eased her on to kibble as I thought that was the best balanced diet. Your found pup is probably in some emotional turmoil with adapting to a new place, missing her owners and home, along with the ordeal of being out in the weather when she was found. So, eating a little less is to be expected. If you can feed chicken & rice for a few days, while still offering the kibble, that might at least be a way of getting her calories in.
Did you look through the sticky about lost/found dogs? It might help to make sure you cover all your bases. I would definately contact the shelters and animal control. In some places it is the law that you contact animal control. Vets in the area are another good place to take a 3X5 card with your info. They usually have a bulletin board and will let you put up a card for a found dog. I would try to place an ad in the newspaper too -- that is usually the first place owners look. Many times they give you the ad space for free when you are reporting a found pet.
You may wind up never finding the owner so it is good to think through what you will do in that situation. Are you willing and able to take on another pet at this time? If not, then I would have the nearest rescue organization all scoped out and contacted in advance. Unfortunately, many of them are full at this time of year -- not sure if it is the weather or economy or combination of both but hearing they are all being pushed to their limits. Another option would be trying to rehome yourself. Not always an easy thing to do -- as you have to try to do some background investigation without scaring them away. Takes a balance of tact and diplomacy along with sleuthing skills.
YT members are a great place to start.
Bless you for taking care of this little one. I know it means a lot of extra work, getting her all cleaned up and trying so hard to find something nutritious she will eat along with tracking down the owners. It may come down to it the only thanks you will get will be a wet kiss and a wagging tail -- but for a dog lover, that is usually enough! Still -- add my thanks in there too. Without you and your brother, this little one would probably not even be alive.