I don't know of any breeds with that coloration, and size so I'm gonna go with mixed breed. Maybe with leghorn. She's at least 2 years old. If she lays regularly then go with 2-3.
Those are very long waddles for a hen, so I suspect that means she is more than a few years old. Probably a mixed breed I guess, because of how patchy the coloring is.
The older they get the more the legs thicken and the scales are more pronounced, I'm guessing your girl is fairly old at least three, probably a bit older, looks like a leghorn cross, maybe with Wyandotte.