> To continue this one step further, if I may. If your statement is
> correct, and no doubt you're right "Why do we cull the Queen?"
> That's a bit like killing the messenger if you don't like the news!
> This practice has gone on for years, if you find chalkbrood, then
> requeen whereas ventilation will fix the problem! Does anyone want
> to comment?
 
There are some strains that are more susceptible to CB, and
requeening quite often helps.  We find that under identical
conditions, some hives will, and some not have CB.
 
Rejecting any hives that have CB mummies on the floor from our
breeding pool has resulted in a major decrese in CB visible in our
outfit -- for whatever reason.
 
Regular requeening is generally a good practice that is becoming even
more important as we are encountering more pests and diseases that
require that our bees have the ability to reproduce quickly enough to
outpace them.
 
Young queens are generally considered to be more prolific.  But who
knows, maybe some bees just ventilate better??