Cooper jumped the Ex-pen then we put a lid on it and he could push the lid open and climb out. For a while we had to bungee the top to the Ex-pen. But now we watch them close and crate them when we leave if we don't take him with us. Which we aren't right now because he gets so car sick..
They do make tops for the Ex-Pens though, that did save us for the winter.
Good luck
Hugs
Cher & Cooper