Well, if she's an escapee, she couldn't have gotten too darned far!
And IF her people aren't knocking on doors or taping flyers on mailboxes down the row, maybe they aren't really worried.
Maybe - for whatever reason- they thought she was a cockerel..?
Or... better yet

... maybe they bought a mixed lot and she was the ONLY pullet

and they knew you had a flock..?
Gosh, who knows?
But it sure is lucky YOU happen to be a wonderful space for her, eh?

And that your flock is pretty welcoming is a good sign.
You'll want to look her over very carefully to make certain she doesn't have mite or anything, might want to go ahead give her a good once over for any foot issues and maybe dust her with some poultry powder for good measure.
If the eggs are thin, she might need calcium. Show her where she can find that. Maybe that will help...?
If she is a production chicken that sprang a 'big place'- I say- GOOD

!!
She SHOULD be!! That is no way to live!
More power to her- and you- and whoever helped free her! Lol
I don't feel badly for whoever had her first, if they were looking for her, you would know it.
That bird didn't take a 474 trek to find you!

She can only walk so far as those lil feet can take her- and she made in ONE PIECE

- so- not that far!
She's meant to be exactly where she is!
Good on you!
Even better for HER!