Bird feeders bring in rats and mice too. I have several feral cats that live around here and they rarely bother my feeders , but they do hunt the mice and rats at night around the feeders. I feed the feral kitties and they live in my greenhouse in the winter(yes I put in pet doors for them...lol). They have all been spayed or neutered by someone else. I suspect they are getting dumped around here from time to time. There are 3 that have been around for several years now.
I’m part of a program set up by the ASPCA called (I think) Capture, Neuter/Spay, Release. I took home two ferals (with microchips and rabie shots), a tiny shelter, and freed them in my backyard. I feed and water them everyday. One is less afraid of me but the other is a real tiger! She resents having to take food from me and turns over her water bowl every night with real violence. But she still comes and eats...