@JoT:
As I understand (and I am happy to be corrected), these puppies came from the same general area that the previous Avongara puppies have all come from; the location where the majority of native stock founder basenjis have come from now.
Just because black is the dominant color on the locus of the carrier, does not equate to black as a color "dominating" the population. It is entirely dependent on selection pressures of the population. A dominant gene doesn't spread (increase in frequency) unless favored by selection. To increase in frequency of a population there has to be selection in favor of one or another color. There needs to be some "advantage" to the color (either real or perceived) by the population who make the breeding selection. What you have is a relatively uncommon gene which happens to be dominant and thus readily apparent when it is present. Since the presence of homozygous individuals does NOT increase the frequency of the gene (absent selection, or genetic drift), the proportion of black individuals in the population should remain approximately constant over time unless there is some dramatic shift in the selection pressure. Dominance does not equate to prevalence in population genetics.
And of course we know that black is a mutation of the beta defensin gene.
Thanks, Jo for the genetics correction and lesson. I believe they said that red was still the overwhelming color present so I guess any changes in the relative percentage of black dogs in the population as a whole are still pretty small. I was just looking at it from a little too simplistic perspective knowing that by chance, you sometimes you get all black (or vice versus) when breeding to a red in a litter, so over a few years span you could locally have a relatively larger number of blacks appear. But that fluctuation probably would correct itself over a pretty short period of time.
So, I'm guessing the "they were unlucky seeing them the previous trips" is the prevailing hypothesis then?