I wondered about that because of the name. She has 4 toes, not 5. And her skin is very white, not black. But mystic onyx can have a little crest like hers. Supposing she IS half mystic onyx, and supposing she really is an olive egger, what blue egg breed would explain the leg feathering?
I bought this chick labeled as an "Onyx Olive Egger" from a farm store in Colorado. She has white black washed legs with two or three feathers on a couple of her toes. Single comb that is black in color so far. Plumage is coming in mostly black with faint flecks of copper brown here and there...