There are many reasons why young queens do not start laying.
 
Was the queen mated before you introduced her to the hive?  If you
introduced a virgin queen, and then had poor weather, this would have
delayed her making a mating flight.  The introduction of a frame of
brood may have coincided with a mating flight and her subsequent
laying.
 
When did you introduce the new queen?  If you did it recently the bees
could have been slowing down for autumn/winter.  The queen stops
laying and the workers don't feed her as much.  Introduction of the
frame of brood and bees would have changed the bees' behaviour and
could have brought about egg laying activity from the queen.
 
If the queen was introduced during poor weather, and then you have had
a run of fine weather, this could account for the change in
behaviour.  WA much rarer possibility is that you have a virgin queen,
not producing queen substance which suppresses breeding activity in
workers.  One of the workers introduced with the frame of brood could
have become a laying worker.