I would definately have your snakes in a completely seperate room with a closed ferret proof door, or vice versa. Ferrets will kill snakes, birds, fish and many other reptiles and amphibians. They're a lot like cats, if you think a cat would be a problem, then a ferret will be twice as bad. I would also suggest, if you haven't already, that you do a lot of re-search before you buy a ferret. There is a lot more to taking care of them then petstores let on or know themselves.