Even two Arabian horses can throw a foal that looks like a pony! And with poultry it is just so astonishing how many variations there can be! Absolutely amazing reallyTrue, but one of the most common (not exhaustive) characteristics of the americaunas are beard/muffs. Her egg color will help. I still think she's a barnevelder cross. If she lays dark brown or dark green eggs, that makes it a higher possibility
I have a bird straight from a reputable hatchery who doesn't fit breed standards at all, but does fit a cross between 2 breeds. It can happen anyway.

I would say she is a lovely red hen with lovely red head

