Hi DR, .... chalkbrood, i experienced the same thing in some colonies that that have always been clear, requeened the worst but with the others the chalk disappeared as quick as it arrived. I reckon the bad weather causing constant dampness was the underlying cause
re Stats and sex alleles in a closed population (thinking of colonsay), With 50 hives with a 12 sex allele population it would theoretically take 30 years to loose 2 alleles resulting in negligible brood variation (T.E. Rinder, Bee genetics and breeding, 1986, pp249) The amount of inbreeding or numbers of sex alleles can be simply estimated by estimating the numbers of eggs that fail to hatch eg 2 sex alleles gives 50% failure, 3 = 33%, 4 = 25%, 5 = 20%, 6 = 17%, 7 = 14%, 8 = 12%, 9 = 11%, 10 = 10%, 11 = 9%, 12 = 8%, 14 = 7% This is a rough estimate, you must use open unsealed brood 70 hour old to count ie patches of larvae all the same age, not sealed brood, and does not take into account whether sperm is well mixed in the queens spermatheca. Use a cut out card to isolate 100 cells and count the empties including both pollen and nectar. (Ref S. Taber, Breeding super bees, 1987 ) you should not pick the best area of the comb.
queen viability - if you count 10 out of 100 unoccupied cells the viability = 90% .... simples. The recommended "good viability" should be 93 - 95% and is what you would expect from any queen bought from a competent queen breeder
So lets get counting !
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