What are your feelings as to whether there tends to be any difference in disposition among blk, vs. ylw., vs choc?
It does occur. Just not common, like you said.It's not the color it's the breeding. I've blacks with the same behaviors you describe, and talking to others who have dogs with such traits; they can usually be traced back to common ancestors. That said there are more black labs period, in performance stock; so it's easier to find a better all around "more balanced" dog; without having to get super in-depth into pedigrees or breeding. Where as yellows and chocolates while they are getting easier to find nice ones in performance stock, it is still harder to find balance of "ancestral quirks"; without really getting into pedigrees and ancestors. There's been more focus on developing Yellows for longer. It was also easier to add yellow to pedigrees as the yellow coloration is a separate gene that covers black. Separate gene made it easier to have yellow show and integrate in several different lines (more ancestors). Whereas the chocolate and black loci compete against each other, you have to select against black to get chocolate= a smaller ancestor pool. Although at least now nice chocolates are not a once in a lifetime mythological creature. Still if you look at breedings, I can find almost as many blackxyellow breedings as yellowxyellow breedings. When I looking at chocolate breedings; almost all of them are chocoxchoco; and I've been looking for particular blackxchoco breedings for many years; they don't come up very often. Heaven forbid we do a blackxchoco breeding, with no regard for color; just to add more balance-options to the chocolate lines. Or the unicorn blackxblack breeding throwing chocolate pups; who's pedigree is so good that they end-up with the right people regardless of color (Roux and Drake) like to see one of those again