It's not a direct answer to your question, but I find the PVC boards very useful for cage building and much easier to source in lieu of the sheets. Maybe these are a workable alternative?
They are readily available at two of my local Lowe's.
Home depo an lowes do carry it "if" in stock. Ship to store is an option "if" in stock. I have not found any in stock near me. I have found half sheets, an that's fine for small stuff.