When using a flat excluder that has no rim and when there are 10 frames below and 9 frames above it, (for those running 10 frames in the brood boxes and 9 frames in the honey supers), the excluder bisects the bee space between the two boxes and in combination with the frames not lining up with each other causes significant restriction of movement up, down, and sideways.  This is not as much of an issue when the number of frames above and below the excluder are the same and they are lined up, and no issue at all when using a rimmed excluder that provides bee space above and below it.

I haven’t been using excluders, but I’m trying them on a few hives this year as part of a trial on swarm prevention.  On the hives that I am finding the colonies all the way to the top of the stack and with empty boxes at the bottom, and as an alternative to reversing hive bodies, I am pushing the queen down to the bottom box below an excluder and letting the colony start a new brood nest down there.  In the few weeks before our main nectar flow arrives the brood will have hatched out in the upper boxes thereby making that room available for nectar storage and hopefully preventing the backfilling of the broodnest in the bottom box.
             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html