Piper likes snow, she hops like a bunny in it and sticks her nose in it. She doesn't seem to mind cold weather as long as there is no wind. I worry and call her in while she's still playing. I worry she can get stolen even though we have a wood fence and they only have access to the backyard we can see from the back door and living room, and I worry that she can become ill or sick form breathing too much cold air. How long is too long for a bulldog in below freezing temps?