Cats have a natural disposition of being independent. They stalk and hunt very well too. The kittens will learn feral behavior from their ****** so keep the kittens inside as much as possible for at least a year. Even after that, keep the cat in the house as much as possible. If raised to a litter box, you can move the box outside and train them to give signals when they need to go. After a while remove the litter box and they will find their own place outside. By this time they have learned that home is where the food and warmth is. Eventually you get a cat that can come and go as she pleases without any problem of them running away. I was raised with cats and this system never failed.
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