Re: Brood Chamber: 9 or 10 frames?
Bees will draw out the depth of the comb to suit their purpose. Brood comb will be shortened to accommodate brood. when they then want to store honey or pollen in it they will lengthen the depth again. this is what gives the white wax effect of honey being stored. Since brood comb is a set depth reducing fraems in the brood nest would be a waste of space. I have never tried the 11 fraems in the brood nest.
Significant Minority vs Insignificant Majority, 20% of causes produce 80% of the effects.