I have been using the "nuc method" for requeening for many years.
Today I just verified acceptance in 50 nucs on top of as many colonies.
Only one was qeenless (the queen was dead in her cage!).  But this method
is in fact labor intensive.  It has the great advantage to give wonderful
acceptance even in the worst circumstances.  It allows for safe
requeening even at the end of the season.
 
There exist an easy method to requeen with cells without searching the
old queen.  Just introduce a cell placed in a ripe cell protector in a
honey super where the bees are working.  The virgin hatches, goes down to
the brood chambers (provided you do not use a queen excluder), fights
with the old queen and survives most of the time.  I do not use this
method myself but I was told that approximately 60% of the queens are
replaced every year if this method is applied to all the colonies.  Of
course there is no queen laying for a certain time.  I also imagin that
this method should not work very well if the hives are placed in a way
that there could be some drifting of the young queens returning to the
hive after mating.  This method is not perfect but I think I would
consider using it if I was a honey producer with a couple thousand hives.
 
 _______________________________               ~
|_____JEAN-PIERRE CHAPLEAU______|       ~       bee breeder
  |1282, rang 8, Saint-Adrien,|              ~
  | Quebec,  Canada,  J0A 1C0 |  vice president of the Canadian Honey Council
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