I was going to suggest the same thing. They do work. Here are some pictures:
http://nordykebeefarm.com/forum/forum_posts.asp?TID=17&PN=1
These can simply be screwed on when needed. A thin strip of wood can be
used to close the top off too should you want to move your hives.
George-
Randy Oliver wrote:
> Jeff,
> have you tried robbing screens?
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