I thought the tail and stance look legbar, feathering, legs and color look cochin.Interesting, cool looking bird! Can't say I've ever seen anything full bred like her.
Crest looks like a legbar's crest, feathering looks cochin-ish, but the tail and stance is all wrong for cochin. Leg feathers say maybe some silkie or cochin, or possibly some Marans mixed in?
I'll be curious to see what some experts think
Whatever she is I would love some hens like her!