Breed?

[Gray Farms]

Try to locate her owner. If you can't find the owner. Quarantine for 30 days as far from your birds as possible then integrate into your flock. She does seem to be Black Copper Marans.

 

[Egghead_Jr]

Do you suspect it was a drop off in your yard or that it wandered in on it's own?

She'd be local if traveling on her own. I'd not think even a mile radius of you. Would be easy to find owners.

 

[CluckerFamily]

That’s a thought... I wonder if it was a drop off also and the people thought it was a rooster instead of a hen.
Do you have any people near you that also have chickens?