I haven't reached the point of needing to replace a Queen because of her age yet but this part always puzzles me. My first Queen hatched in June 2009 and the bees superseded her the following May at which point I managed to make gain another colony from it too.
Some state you shouldn't have a Queen more than 2 years old, and others say it is in the August after her 2nd full season that you replace her.
So I have 2 Queens raised in May '10, provided that they perform well would I replace them in August 2012 or should it be earlier/later.
I've read some people advise to requeen in March using a Queen from a nuc brought through the winter, however they're based in England- would that be a benefit in Scotland?