Maybe it is the hive box? How old is the hive?
Did you paint or stain it recently? If so, with what
and when?  Did you treat the inside of the hive (boxes,
bottom board, inner cover, outer cover) or the frames
or foundation with anything? If so what?
 
        Sometimes the bees just don't like the
accomodations due to residual chemical odors.
 
        Jim Moore
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