Ferrets do not have very good depth perception, so they are prone to falling from heights.
Q: I own two 2.5-year-old ferrets. I am getting ready to move into a loft apartment. Should I worry about my ferrets being brave enough to jump through the gaps in the railing at the top of the stairs?
A: Ferrets are naturally curious and, unfortunately, they have very poor depth perception. There is always the chance that they could fall through the bars not realizing how high up they are; or during the excitement of play one might chase the other through the bars and down they would go.
The best thing to do for their safety, and to preserve the view of your balcony, would be to install sheets of Plexiglas against the bars. This would keep your ferrets safe and be aesthetically more appealing to you. Make sure the Plexiglas is at least 26 inches tall. Most ferrets can jump up and grab the tops of barriers that are 24 inches high or less.
Be sure to keep furniture away from the barrier or your ferrets can use it to boost themselves up and over the barrier. If you need to keep the ferrets at the top of the stairs, you can build a Plexiglas “door” to go across the top of the stairs. Frame the Plexiglas with wood strips to make it sturdy. Attach it with hinges to the wall at the top of the stairs and put a hook and eye latch on it so the ferrets can’t push it open. If you prefer, you can put a hinged barrier at the bottom of the stairs, but if the stair rails have slots going all the way down the staircase, then you would have to attach Plexiglas along the whole length of the stairs to keep your ferrets contained.