
Thing is there are lots of a breeds traits, that distinguish it from any other that really have nothing to do with it's working ability.
In the ESS for example, length and shape of the ear, colour, to a large extent head type and eye shape, other than any unhealthy exagerations, and obviously a soft mouth and decent jaw are irelevant to it's job.
An ESS is supposed to be Liver or Black or Tri with white, but it could still work if it were solid yellow or grey, had pricked ears or what have you.
In the same way in my breed a dog that was a poor colour had extensive white markings, light eyes, no mask could still hunt Elk, but it sure hell would be a poor looking specimin, and in fact that is exactly what many work only dogs are.