We put a cat flap in Bon Bon's puppy pen so he could go in and out to avoid his big brother. Then we realized that he hated to push the door open with his head. We put a drain pipe with an elbow in front of the cat flap and propped it open with the elbow. It didn't take long before Bon Bon was stealing his big brother's smaller toys and dashing off to his pen to play with them in peace.
Arthur looking at where his little brother went.