Carson did the same thing in his petyard when he was very young.... Finally I bought sheets of plexiglass, drilled holes in the corners and ziptied the sheets to the inside of the pen....he still jumps really high, but his feet can't catch the edges and hold to allow him to climb out... he just slides back down.
The problem with him climbing out was that he'd get to the top, then not be able to jump down safely and he fell a couple of times, hitting his head on the laminate flooring! Yikes! I was so worried he'd get a head injury so we took care of it right away.
Good luck on finding a solution. the pen I have is available at Petsmart, Petco and Petedge. You can expand it to make it larger and it's fairly easy to fold up to take with you but kind of heavy with plexiglass on it.
deb |