Ideas to make crate smaller

Hi there, having problems... Our crate for our puppy is a bit too big for him so we've been cutting half of it off so he only has enough room to turn around in. However every idea we come up with turns bad... We had cardboard in there to cut half the cage off, but he chewed that today. Can't use blankets he would chew that. Only thing I can think of that he wouldn't chew is metal but we don't have metal lying around. How you do you guys cut off the cage while they're so tiny? I also think he may be hurting himself in his crate. There is no room to move around in, but he jumps up and down we've noticed. Today when we came home he has a little cut on the top of his head, could be a little pimple but looks like a little cut to me. Does anyone else encounter problems with their puppies hurting themselves in their crates? He's great in his crate for the most part, no crying, no accidents, its just when we first put him in that he does all this, after that he settles down and is okay. Any suggestions? Thank you everyone:)

You can buy barriers. You can also have a piece of plexi glass cut to size(little smaller), drill holes in the corners and use wire or tie wraps to hang it in place. You could use wood but it can easily be chewed and could be a hazard.

In another thread there were some ppl who mentioned putting a rubbermaid container (or similiar) in the back part of the crate to make it smaller. I am assuming that you have a wire crate. If so, you should be able to buy a wire partition for your crate model. The partitions can be moved backwards as the pup grows.