So, our little Netherland Dwarf bunny BlackJack is 10 months old and has been fixed.  We’ve had him for about 3 months then decided to get him a friend to play with and keep him company. She is a dwarf bunny but not sure what breed she is. After getting her we built them a play pen for them to hangout and live in. And upgraded their litter box and litter. While we had just the one bun we were using Critter Litter premium potty training litter. when we got the other bun we started using Wood pellets. because it was going to be cheaper. So the first few days on this wood pellet litter Blackjack started digging out the litter all over the place and started jumping up and down. So right then and there I knew he was unhappy about something  So I switched litters again to another brand of Wood Pellet.  He seemed to like this one better. But recently After I cleaned out their box and refilled it He did it again.  And Again!!! Can someone help me figure out whats wrong with him please???? As far as we can tell he is the main Culprit. She seems to be pretty chillaxed even with the big mess.