I start my litters out in a playpen. I replace the mattress with 3/4" plyboard. I worry they will get under the mattress somehow. I also worry about mold spores and mildew from messes and/or being stored. If you get a 2nd hand one, make sure to clean it thoroughly with a bleach and water mixture. Then make sure it is dried and aired out. When I got Cowboy as a puppy, I put him in a crate on a nightstand right at my bedside. I could put my fingers in there to comfort him if needed. He has been awesome from the day I got him....but that's another story
