Damn sorry to hear that, I have to orange cats about three years old and I started letting them out when they were really young. One of them got hit one day and her leg was snapped right in half. Had to pay $13,000 for the surgery but you can't even tell her leg was ever broken now. But yeah it's tough man, you want to let your kittens out so bad, but the chances of them getting hurt that young are high...