My new friend

Have seen this barn kitty walking around the perimeter of our property for a few weeks and a few days ago I walked out to the back porch and chatted with her. I said, "Come on over here and visit." and she did. I sat on the back porch and just petted her for the longest time. She was so sweet! I cannot tell if she is someone's cat that just lets her roam or if she was someone's cat that got lost. Either way, she is tame, has a nice coat and sits on the back porch waiting for more love. I know she is eating 'cause Charles saw her the other day with a mouse and I took a few bird feathers out of her claws yesterday. But of course, I gave her a few kitty treats and now she is my best friend! She is my outdoor shadow. She walks with me whenever I take the dogs out. Kiwi loves her-they rub up against each other on our walks. She sits in the outside part of the open window just watching us inside. Elphaba doesn't like her one bit and they hiss through the screen. I just have one question...what happens to outdoor cats in the winter?