I am looking for a good playpen for my rats. Due to rules from my parents and rats hiding and/or getting stuck, I need to use a playpen when I take them out of the cage. I want one that is large so that I can sit in it with them, and tall enough so they can't jump out. Also I need it so they can't somehow climb up and out. I have been looking, but can't find anything. Any suggestions?I'm not opposed to homemade, but it needs to be easily folded and stored. I tried cardboard, but it was hard to secure and a pain to fold up, set up, and store.