Elliot is 2 lbs, and has a four level ferret nation cage, and large Xpen.Leaving the Xpen up all the time, instead of putting it up once a day has changed Elliot in a positive way. He was being a bit cage aggressive, and shy. Now he will come up to us, and sit and enjoy being petted. I think he no longer feels so closed in. I only take it down now to clean or if I need the room to do a water change on my aquarium.1-2 days a week, for a couple hours or less. He still gets to come out for a good run, but the Xpen has really expanded his home a lot.