I see lots of signs when I'm driving for free kittens. Someone dropped off a pregnant cat that my son found in the woods behind our house several years ago. We posted signs everywhere, did everything we could to find her owners, but no one ever claimed her. So, we took care of her and helped her deliver her babies. When they were old enough, I did give them away, but I made sure they all went to good homes. We still see all of them from time to time because they all went to people we know.