>Does anyone have a Yellow or Red marked queen still working anywhere?

Yes, lots.

Reds are not routinely replaced this year, and yellows as the
opportunity arises.

After we have completed the requeening process for this season (ends
this week) we will still have around 300 to 350 Reds and about 50
yellows in service to go into the coming winter.

We also had approx 15 whites and one blue this spring still active and
doing generally well, but we have since raised a crop of young queens
from these long lived old ladies and replaced them with some of their
own progeny. A certain proportion of older queens, including a good
number of the yellows of good strength, sportingly supercede which saves
us a lot of work. (We keep them under pressure to lay which encourages
this to happen)

Important point though is that these are A.m.mellifera blacks, or
crosses including them, which tends to be longer lived than our other
strains anyway, and it is in Scotland where our seasons are relatively
short, so queen 'burn out' does not happen so quickly as in areas with a
longer season.
--
Murray McGregor