Holy Crownboards?

There's much discussion (and yep I mean arguements) on the various beekeeping forums about whether or not hives should have holes in their crownboards for ventilation. The crownboard is a basically a ceiling for the hive that goes underneath the roof. Some of the old beekeeping books say  you need those holes for ventilation, some say you don't and some don't mention it at all. Back in the day wooden beehives all had solid wooden floors, since the fairly recent arrival of the varroa mite there's been a shift to wire mesh floors which the mites can fall through -that's usefull because it lets you work out how many mites are in the hive and so on, also any mites that drop out aren't bothering your bees anymore. Of course replacing a solid wooden floor with a wire mesh means you've suddenly added a load of ventilation to your hive.

Crownboards often have holes in them for a couple of reasons, to let bees in or out or to allow access to a feeder. After looking at the various arguements for and against leaving the holes open these holes I thought the bees probaby have a far better idea of what they want than a lot of people arguing on the internet so I'd let them bees decide for themselves.

I stapled a mesh to a little frame and popped it over the hole. A few hours later the bees had propolised it into place, If the bees don't want ventilation they'll block it up, if they do they'll leave it open. Simple as that. Also if they want more or less ventilation they can block up or unblock more of the mesh  as they choose. Not really rocket science is it? Three days later here's the mesh:

Grille over crownboard hole

The bees had reduced the hole slightly but not hugely. I've seen how much propolis this hive can lay down in a short time so I know they could have closed it if they wanted to, probably in winter they will. I'm not entirely sure what the bees on top of it are doing but they seemed happy enough. I still have the other crown board hole open near the front of the hive -so the bees can access a reserviour of used wax and propolis but more on that in another post.

For anyone wondering what propolis is: it's basically bee glue. The bees make it from tree sap and it's sticky as hell. It's used by them to block up holes and gaps in the hive and works really well. They also use it for things like entombing dead mice in the hive if one's managed to get in and then been killed.