Hi Adam, the mesh is to keep the bees in place, they have kingspan on top of the crown boards. When I need to feed it is easy to slide the mesh across and put feed over the hole.
I suspected that would be the case - any new beekepers lurking might have not known about the kingspan on the top and thought that you left the top open for ventillation, hence the question.
I suspected that would be the case - any new beekepers lurking might have not known about the kingspan on the top and thought that you left the top open for ventillation, hence the question.