Check the cold dark places as well. It never fails my bp's always go in back of my record shelf. It is not the warmest place but it is low and dark (and hard to get to). Get on your hands and knees and follow the walls. If you see a small place it could get out or hid check it. They can get into the smallest of places. Good luck and I hope you find her.
P.s I would also let your dog (or cat) out on a leash. Watch it closely they might be able to find it for you. Just make sure you can control it. My dogs and cat seem to find anything that gets out (snakes, rats, etc)