I work at a reptile center where we house a 13 foot burm. Is has a very large cork bark hide that it fits in nicely, and seems to enjoy. As far as the bigger boas (6-9 footers), they don't have hides. I don't think they necissarily need any, since they aren't NEAR as shy as ball pythons. If I were to notice them roaming around their enclosures, or going off feed, I would throw in a cork bark hide for them to see how they like it.

That's my thoughts.

Jennifer