Let me start by saying, I am really sorry and I am in the same boat. Also, before this rant please know I LOVE CATS! Love them. However, my neighbor thinks she is a wildlife rehabilitator despite not being trained or certified. Thus, all she does is feed wildlife - skunks, racoons, feral cats, etc. The cats use my lawn as a catbox. Sadly, I have no solutions to offer you since we are in year two of this nonsence and she promised to stop feeding them last summer, but they are back. In fact, one of the feral cats just abandoned kittens on my porch (one dead and one that cost me a lot of money and then died which was really sad). This is all I can suggest - call the township and depending on where you are they may help. You are mostly on your own if you are in unincorporated Des Plaines because then you will have to use the Cook County Animal Control who will do the following (and no more) - drop off/pick up traps Tuesday - Thursday. You have to call the morning of and ask them to deliver traps - I was never able to actually get them to drop off the traps because they were always all out of traps by 9:00AM when I called. You must be home to get the traps too, they will not just drop them off. Also, you need to bait them with food and you have to call them to pick up the animal. They will, again, only come Tuesday - Thursday 9:00AM-4:30PM. Good luck getting animals being fed nextdoor into traps in your yard - you will likely have to work with the neighbor for that. There is a local TNR (Trap-Neuter-Release) group, but they never responded to my emails - you may be luckier (link below). Finally, I only found one local exterminator willing to help with TNR (they will rehome the cats to an existing cat colony), but it is crazy expensive. Thus, here are my solutions - last year, I actually used an enzyme spray to get rid of the smell. This took me forever because there were pounds of poop every week. This year I am trying diotomaceous earth. I am going to put it on the cat poop to kill any parasites the cats carry. I am also going to use sprinklers and hose any cats in our yard. I am not super hopeful. We are also getting a dog, but that was in the works before this cat issue. You can also try fox urine (at Meynards - I've been told is smells bad), cat repellent spray, or use orange peels. I had no luck with the cat repellent or orange oil, sadly. Fox urine is supposed to be pretty smelly. Sorry I can't be more helpful.