>     On the fifth or so hive, I smoked them lightly and opened the box
> whereupon I was jumped by about 10 drones.
 
If you have an excluder on the hive and some drone brood has been left
above it to hatch  -- and if your equipment does not have the leaks that
much commercial equipment has -- then the drones cannot get out to fly
after they hatch.  That is until you open the lid; they can then explode
out of the hive like a bomb going off when you lift the lid.  This
particularly true if there are many, if they have been pent up for long,
and if it happens to be a hot day.
 
I don't know if this is what you experienced, but might help explain it.
 
Allen
 
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