Second, are these kitties truly feral, or are they just homeless? Huge difference, especially for the babies and the ones you suspect of being abandoned pets. I would say even if they are feral, most can become, at the very least , friendly with their feeder.
If you have youngsters or kittens out there now, trap them first. They are adoptable, plus they are cute, so people will want them.
Talk to your vet and look in your paper. There are probably kitty rescuers in your area, and maybe even groups who can help you if they are really feral. We even have houses that are dedicated to nothing but homeless kitties.
I'm really surprised at your Humane Society. Perhaps you should talk to another person there, or trap the nice ones and take them there to be adopted. Tell them they are abandoned, not feral.
Depending on how long it takes you to catch them all and disperse them, you might consider getting the mama kitties fixed, or the problem will just get worse. I know my vet will take in homeless pregnant mommies, delivers the babies, and adopts them out herself. She even has one kitty that lives in the office who was a feral pregnant mommy. She is not really fat, happy, and loving.
Good luck. You might even look on the internet to see if you can find more information, or perhaps a rescue group in your area.
