I have nine ferrets, and use the playpen. I have it set up four panels by three panels, so I guess I added two expansion sets to it. (It's been done over a couple years, so don't recall exactly how many it originally comes with.) It's escape proof (for my ferrets anyhow, a couple of which are climbers/jumpers) and with the size I'm using, it seems to be plenty of room for them. I have tubes, literpans, food and water, bedding, toys, etc. in it, and there is plenty of room. My ferrets are all older, the youngest is about five, and the oldest is age unknown but ancient, I'm not sure that long-term it would be appropriate for a couple younger ferrets, but for a month, even if you have six month olds in my opinion it's fine. Anne [Posted in FML issue 4532]