I was wondering if I could make a 6-in tall barrier to keep shavings and poo relatively inside a ferret nation, rather than flying outside of it. If I can, what would be the best way to attach it to the cage?
Yes, just bolt/nut/washer to fix it to the cage after holes are drilled. And as I said above, mine did not try to chew it but if they had, I'd have removed it.