One of my rabbit have a lot of energy and will often chew the bars of his pen. The pen is 75 sq ft filled with chew toys, he can dig, jump up on places but he still chew the bars of the pen. He’s an outdoor rabbit, which make him less nervous and stressed as he was indoor. He will become indoor rabbit when he’s more secured around humans and is bonded with my other rabbit. He dosen’t have good sight which make him really scared and insecure among things that moves around in the surroundings. But I have come a good way on making him secure among humans, only have the step to make him used running around indoors with more life around him. I’ve tried most of the things to stop him to chew the bars but, he want to run around more. I know he wants out from the pen, he have escaped sometimes but always comes back when I call his name. I can’t take him on a harness like my indoor rabbit because he easily get scared, so it would be dangerous to put him in a harness. I can’t make the pen bigger and I let him come indoors to run around but this can’t happen too often, otherwise he will regress and become more scared among humans again. I can’t let him run loose because he move faster than what I can, so not safe at all. So how can I keep him away for spending time chewing the bars.