Do a search for Croad Langshan. They can have yellow legs.
The first importation of Langshans into this country was made by Major Croad and, as with other Asiatic breeds, controversy centred around it. Already there was the black Cochin and then the black Langshan, some contending both were one breed, and others that they were quite separate Chinese breeds. As developed here the breed was called the Croad Langshan after the name of the importer. In 1904, a Croad Langshan club was formed to maintain the original stamp of bird. The Modern Langshan has been developed along different lines and, in consequence, the two types are shown in separate classes at shows.
The body type matches a Langshan but it is correct, they should not have yellow or green in their legs but instead black and blue. Didn't notice that earlier. She's probably a mutt. I kinda doubt she's a poor quality Cochin, as her body type is pretty extreme to be such.