is the front made of mesh or of mesh-in-glass? The frame looks a bit heavy-handed (so to speak) if it is just holding plain mesh.
I think it's just mesh (it's actually one piece of mesh right up to the top of the overhang; you can see it curve), but you're right that the frame looks rather chunky. We did have a tour and I'm sure something was said about the future or former use of this exhibit but it has slipped my mind in the interim. Maybe one of my fellow Zoohistorica-ites can recall?