Though there's a little age difference here, I'm having the same problems with my (Chihuahua-Rescue) Navi. Her previous owners must have never fed her any dry, and that's all my other guys eat (besides treats). She seems to be totally "table scrap" orientated.
So, I'm feeding her "some" scraps, but only just enough to sustain her. It's been about two weeks now that she's been here, and I have seen her nibble at the (available 24/7) three types of Dry Dog Food I have out. It may be that She has eaten more than I think, given that She has access to the Dry Food, much of the time when I'm not looking.
Slowly but surely She'll come around, yours probably will to
