I was thinking into buying a cat tree/condo for my ferrets but I was afraid of their clumsiness. They have absolutely no balance and when they get hyper playing together they fall off of the couches, bed, tables. Would anyone recommend a certain size. If I was going to buy one I would not be interested in a single level one. So, I'm not sure if it would be worth it in less it was multilevel. Some examples would be great. Maybe someone has modified theirs to make them more "ferret" safe, lol. I'd hate to just go out and buy one and then have an accident with one of my fur babies and feel guilty. 

Thank you :)

[Cynthia, Daisy, Duke, & Bear]

I was thinking to run tubes up through them to give a safe way down.