Material for outside of pen to stop mess?

Hi all

I have a large pen in my room for my 2 bunnies. http://www.zooplus.co.uk/shop/small_pets/hutches_cages/runs_fencing/pens_with_racks/95235

I have the large version of this. The pen is on top of carpet and they use a litter tray in their pen. Although they are quite good using their litter tray there are always quite a few poos manage to escape through the bars and end up all over my bedroom floor. Same goes for hay. As you can see the pen has 8 seperate panels, I keep it in a square shape. I was wondering if anyone had any ideas of something I could put round the outside about quarter of the way up, so they can still see out but will stop anything spilling out. I would want it to be something that I could attach to each seperate panel so it can still be folded and moved if needs be. And also nothing they could chew or hurt themself on.

Thanks
Sage

Bump??

The plastic thats used to line upvc windows could work and its pretty cheep. It comes in strips of about 2m length and its easy to cut with a hacksaw. The bit I mean is the plastic strip which lines your walls and ceiling around the inside of the window. Do you know what I mean :lol:

:wave: Look up coroplast. Not sure if you guys in the UK have it but I know most people here use it in rabbit/piggie pens.

How about laying a sheet underneath, fold it back and peg it up around the outside of the pen.