Can kitties survive temperatures under 25 degrees F? Mine are outdoor cats, than stay in a pen next to our birds, and we are going to Illinois this weekend and i'm worried about them.. They have 3 walls, and the front is wire. We are going to put plywood around the whole front but keep a little bit open so they can look around outside. Plus a heat lamp through the winter, but we are going to do this after we get back from Illinois.. Do you guys think they will be fine? Thank you!