I have two 7 month old sisters as fosters at the moment. They have so much energy it's unbelievable. The rate they are chewing at I will have no hutch left to take on any more when they go because the hutch will be destroyed. I would appreciate it if you could look at the pics below and tell me what I could improve for them.

The run, time is split 50 50 between run and hutch.

The hutch. I used spares from the cat tree to make a new one for them after they chewed the last one to bits.

I have a couple more. Pics but can't add them from here. They also have two large branches to chew on.