oh my.. i am so sorry.. you can call a pest control or exterminator to help, but cats are considered a domestic animal.. If he has "fed" those cats they are his by law. call your code enforcement or animal control too. Its your property. his animals are killing your livestock and most state law won't allow it to continue. This is just awful. You should not have to be subjected to it, let alone your poor birds!
Message me, i am willing to pm you the links to where you are to contact the right agency to help stop this! Its so painful to lose the babies you have worked so hard to raise and care for
My families all come from large farms and yes at times welcomed new cats/kittens to be dropped off. What happened to the so many I don't know. Today, the counties/states offer programs to spay/neuter at a very low cost. It wouldn't stop them from coming over but would from repopulating if he would have it done. I have 7 cats, all rescues and all indoor kitties now. Is that the best life for a cat? I don't know that either, but it's the best mine are getting. They range from 1-15yrs and are all spayed/neutered. I'm with whoever advised to to call pest control. Do whatever is necessary to protect your flock.