Tom Barrett asked about drone escapes and Lloyd Spear responded.

There are a couple of points I would like to add to the discussion that I have
not seen mentioned so far.  First, several folks talked about a queen excluder
over the top colony, but I don't remember anyone talking about using two queen
excluders, one between the two queens and one over the top colony.  Maybe two
queens excluders are not necessary, but I would think you would want to have
the one between the two colonies to keep the two queens apart.  Second, you
would naturally need to have an upper entrance to allow for the possibility of
queen supercedure.  If drone escapes were used, then a virgin queen would be
able to leave to mate, but would not be able to return to the hive, so you
could lose the 2nd queen in the part that didn't have an entrance.  Correct me
if I'm wrong, since I've never kept a 2 queen hive system, but I thought from
my reading that you would want to have an excluder between the two queens as
well as a second excluder between the top hive and the honey supers.

If you remove the top half with the second queen in it before putting on supers
for comb honey production and allow all the field bees to return to the bottom
hive, then of course you would only need one (if that) excluder at that point
above the brood area and below the honey supers.

If you combine two hives and each has a queen, don't you run the risk of losing
one or both queens if you don't have an excluder between them?

Layne Westover, College Station, Texas, U.S.A.