The poor cat. I feel very sorry for it. It wants and needs to go outside, so put in a catflap. Cats love to go out and explore, to feel the ground beneath their feet and to sniff about. The other two shouldn't be penned-up in a garage either. All three should be free to go outside at any time. If a cat brings in 'trophies', it's to be expected - it's what cats do. It's frantically scrabbling at the carpet in a vain attempt to have freedom. Please please let it go outside through a catflap. And never never hit a cat. It achieves nothing except fear and increases their stress. Oh dear, poor little soul.