As you know I have sort of been where you are before I got Samantha so I know how it rips your heart out. Don't you have the right to put food out on your own property for "strays".. Then that dumps it right back in HIS lap (his cats coming on YOUR property) ... If you want to go that route...

I would back off on the feeding since you know they are getting food daily and see if your stopping effects their weight any. I would keep a close check on the weight and if they get to thin, start feeding them again.

When I had Sambo, he was a very well fed BIG BOY and we lived out in the country where there were plenty of mice.... he was always catching them for sport...

Same with RB Penny, well fed BIG GIRL, use to catch birds, rats and moles for sport. That dentist is full of hogwash!