Jon,
> I have verified that queens which started to lay 30 days
> after emerging were so good or better than 15 day's queens.
A queen starts laying a few days after her mating flight, so if for any
reason she hasnīt gone mating (bad weather conditions, for example) or
if she didnīt find drones in her first fly, then she will mate older,
and will start laying older, but she can be as good as a younger queen
(but of course, there are limits to this).
Tere