Tyvek for covering small squares

So I have a big roll of Tyvek in the barn left by a home builder I know. He says this stuff is designed to let moisture ESCAPE while keeping moisture OUT! Seems like the perfect hay covering and possibly putting down to stack on?? I only found one thread on here that was not very conclusive. Any of you guys tried this?? Thanks to all in advance.
Wayne

Tyvek for covering small squares