I suppose using cats for vermin control is far better then trapping or poisoning them. Let's the cats do their thing, but how do you keep the crows and falcons from getting at the cats?

Most of the time, the cats stay in the barn or other buildings on the property. A lot of the ones that live there currently, from what I have heard... Are descendents of cats that were dropped off and abandoned by their owners. We try to help when we see blatant instances that we can but we aren't the property much (my gf is more for work but it is a half an hour away from our apartment for me.) Eventually, we would like to have all of the current cats spayed and neutered to keep the numbers down.

Mostly what we do is get the kittens homes, feed them with what food we can afford to buy for the farm, socialize them and keep them safe when we're there but without living there it's difficult to do more. It's sad but the honest truth of it is, they're feral for the most part. And farms are not safe places, even not counting the birds. :/