I have been told that the rule of thumb is "three inches or three miles" -
meaning that if you move the hive minimally the bees will manage to get
home.  If you must move it more than a few inches, you must move it at least
three miles of they will return to the original location.  I have also read
that if you seal the hive (allowing ventilation, of course) for one full day
you may be able to move it less than three miles, since the bees seem to
re-orient themselves after beeing "under house arrest" for a day.  I have
actually done that, sealed  a hive with screening, then moved them after a
day. However I must point out that I only moved one of two hives in this
manner, and any bees returning to the original site might have migrated into
the hive that remained there.  /C.Crowell