She's going to be really beautiful when you get the dirt off of her.
In the top photo, I can see the quick of the nail. It is slightly pinkish and stops about halfway down the nail.
I'd say that's a pure Muscovy.
If you take her home, treat her for mites before you take her onto your property and clip those nails so they aren't curled under. Give her a nice tub of water and she will bathe herself.