I'd give it a little more time. I also would not be interested in working with a rescue that takes weeks to respond or does not respond at all. Your time is important and so is the fact that you start to become attached to a pup after seeing it.
Different rescues have different styles. Some are bery picky. Others are not.. Some take teir time placing each dog. Others just want to get as many as they can off of death row.. It is all in what each rescue feels is most important. The yorkie rescues do seem to get a lot of very sick dogs, soit will be harder to place them. Anyway, if you get tired of the waiting thing, there are rescues wuth yorkies that would adopt out very quickly. Actually, the place we got Ry from has one now...unless he has been placed.
Happy searching.
