Depending on where they live, I would imagine they aren't far from the chicken's home. It can be a little awkward approaching neighbors if you don't know they well, but I'm sure it would be fairly easy to spot which neighbors keep chickens. A simple "is your flock missing a member" could be a good ice breaker. I doubt the lonely chick ran too far from home.
Must be a classy bird, though, to stay on the porch and let them take care of it! Sounds like it had a long night.
In reference to the chick photos, sorry, I have no shame! They are hilarious, and I have to share their comedy with you guys. Consider it payback for all the awesome photos I've seen over the past few months while I had no flock of my own! Now we're getting close to even! =P
Cheers
p.s. thanks for the advice on silkies, I can't imagine anyone in the area has any silkie chicks they'd be willing to part with so late in the season--but perhaps you guys could point me toward someone who wouldn't mind selling me a couple?