I want to get an exercise pen for my bunny that will act as his cage until his behavior improves a bit, and he will come out when I can watch him, but I want the pen for when I am not home or sleeping. I saw a few pens at the pet store, but they all said not to use them unless the rabbit was supervised. So, I wanted to see what brands people on here use and where you found them. I also want to know what the minimum size is. I don't have a lot of room in my apartment, but I want him to have enough space, and the pens at the pet store looked pretty small. I feel bad for him since he is going from free range to a pen. Thanks!