Cats kill/eat birds and mice.
My cat was born in the house, well fed every day since, neutered, etc.
He kills birds and mice for sport, and to show his human masters that he is looking after the yard.
Nothing to do with feral.
In my town, a cat is considered a free roaming animal. But if my cat is on my neighbor’s property, he can capture the cat, to protect his beloved birds or mice.
I believe the law does NOT permit him to kill my pet cat over a bird issue.
There’s nothing in the law (that I know of) that keeps anyone from putting out poison bait in their own yard.