Michael, Theferretstore.com sells a hammock called "TheFerretStore.com Ultimate Fleece Hammock" which advertises that it's big enough for 8 ferrets. My 4 sleep in a regular Marshall's fleece hammock, and I've seen 2-3 in the sleep sack (which doubles as a hammock, they can choose to be inside or on top of it). Our Marshall's fleece hammock is bigger than the cheapest super pet plain hammock, but it's not huge or anything...remember, all the ferrets crunch up together when they sleep and don't take up so much space! Happy Hammock Hunting, Chana [Posted in FML issue 4095]