Even when using a grid to determine the amount of brood in a comb I think we
are still estimating not measuring.  Using a grid takes too much time in
calculations in real world field work.  In Washington State we do not have a
requirement for amount of brood in a pollinating unit, just the combs of
bees.  Under some weather conditions in California, colonies may come to
Washington without any brood.

When I measure brood area I always consider both sides of the frame as one
frame.  So I agree with Allen that both sides of a frame equal 100 percent.
For speed in calculating I estimate the amount of brood by eye much as Allen
did in looking at the video.  Brood out to the end bars, down to the bottom
bar, with only a small pollen and honey arch, on both sides of the frame,
equals one frame.  Another way that is sometimes easier is to subtract the
open comb, pollen and honey from 100 percent to arrive at the amount of
brood.  Or, you can open a two story hive by tipping up the second box,
estimate the amount of comb not covered with bees, look down into the bottom
box and do the same (or up from the bottom), add the numbers, subtract from
16, or 20 combs in the two boxes and you have the number of combs of bees at
a given temperature.

Estimating the frames of bees is subjective but can be easily agreed on by
several beekeepers observing the activity.  I have found on numerous
occasions that beekeepers may estimate individual frames somewhat different
than I, but the overall estimate for the hive is usually within 1/2 to one
frame.  Remember that each colony clusters at different densities at a given
ambient temperature resulting in further subjectivity.  But, we are
estimating not measuring.

Here in Washington we have a minimum requirement of six frames two thirds
covered with bees at 65 F.  That is four full combs of bees, but bees don't
cluster that way.  They cluster in an elliptical or egg shape, hence
subjectivity occurs.  In conducting estimates it is most critical to
estimate closely those colonies close to the minimum strength in the
interest of the beekeeper and grower.

I wonder if the "6 to 12 (Yup, TWELVE) full frames of brood" should have
been BEES not brood.  A simple verbal mistake, if it is a mistake.  Twelve
frames of brood would probably have 20 combs of bees during spring
pollination here in Washington.  This colony would soon be hanging in the
trees.  Allen's observations seem to concur with mine here.

James C. Bach
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