Why don't queen breeders sell hygienic queens? I don't know.  I think people are
just catching on to the idea.  We are conducting a lot of research on hygienic
behavior and on the performance of hygienic colonies here at the univ. of
Minnesota. I'm encouraging breeders and all beekeepers to try the test.  I'm
convinced that as soon as beekeepers are out there looking for the trait, they
will also come up with some ingenious and better way to test for it.
 
We use the freeze-killed brood assay to test for the behavior in colonies. The
test involves cutting a section of pupae out of the comb (about 100 cells on
each side), freezing the pupae for 24 hours, then re-inserting the comb into the
nest.  It's important to put the frozen pupae in so that it is flush with the
comb, otherwise you will get variable results, as Jerry Bromenshank mentioned.
We are in the middle of testing whether it makes any difference how old the
pupae are, how long the pupae are frozen, how long they are thawed...I won't
have the final results until next summer.  Sorry.
 
The pin-prick test is easier (as Jean-Pierre Chapleau described), however
killing the pupae by piercing them with a needle through the cell capping
elicits a very quick response in the colonies.  In the freeze-killed brood test
we consider a colony hygienic if they clean out the frozen pupae well within 48
hours.  In the pin-prick test, a hygienic colony will clean out the pupae within
12 hours.  A NON-hygienic colony will remove pin-pricked killed pupae in 48
hours, whereas it takes them well over a week to clean out frozen pupae.  I
prefer the more conservative test (freeze-killed brood) for our breeding program
because I don't want to make mistakes, which I feel are begging to happen with
the pin-prick test.
 
I will try William Lord's idea of killing the pupae with dry ice, but I have a
question.  What does the dry ice do to the cell cappings?  It is important to
leave the cell cappings intact and normal looking (which is another reason
cutting out sections and freezing the pupae works well, and why the pin-prick
test goes so fast).
 
About chalkbrood:  Our hygienic breeder colonies don't have chalkbrood.  Either
do their daughters which are open mated.