We've got a wee bit of a feral adn un-collared cat problem as well. No losses or anything in the area of chickens, but the "pack" wiped out squirrles, birds, and all manner of other furry and feathered thing on our and surrounding property. The neighbors (who are quite nice otherwise) brought four or five with them that are 100% outside cats. There were already two or three ferals on the property, so they are now being fed by the neighbors. Talks with them yielded "Well, we can't really do anything about cats...they'll go where they want". I was less than pleased with that response. We kept an eye on the cats wandering through the property, and if they weren't causing any problems we left them alone. However, they seem to like the gardens...and leave nice little surprises every now and then. This is especially the case with the newest garden we put in last weekend.
Ok....we've tried the mothballs in jars things...that has eliminated some of the problem. Chasing them off with harsh words worked until they got used to the yelling. We don't have the extra cash to invest in the Scarecrow-type electronic deterrents, so that's not an option at the moment. Our local animal control office is swamped with feral cat calls, so there's a waiting list for the few cages they have. Buying a trap or two is an option, but we again get into the money issue.
I have an old BB gun that I have used in the past to dispatch squirrels that infested a past house. I know it will hit hard, but not hard enough to kill a cat in one shot. I am not cruel, so I have not been aiming to kill. A few pumps and a pop in the rear sends them running. That method has worked to keep a few more permanently away.
I do have an adequate number of high-power weaponry that would guarantee one-shot kills, but we live inside city limits. Granted, there is plenty of space between us and our neighbors, but I'd rather not run the risk of puncturing the goodwill we have developed over the past year and a bit.
The persistent cats are the ferals, and I know that a large Tom is living under the house on the second property (run-down house that I need to tear down). The others....I am not sure where they come from, but they are there.
While the cats are not a direct threat to our chickens yet, they do cause damage to our gardens and are a threat to the other wild animals that both my wife and I enjoy. Killing is a last option for me, but it's getting to that point. I have my shovel at the ready and a perfect final resting place for a few of these cats.