There appears to be a genetic link between the rich, glossy green overlay of color and the presence of white. The Runner possesses a more upright carriage than any other breed of duck. Picture a Coke bottle which represents a pretty good approximation of both shape and carriage in the Runner. The head is an important runner feature, also. Condition is often a problem in classes of Runners.
Runners can be tricky to condition for show.
While the body should be cylindrical, underweight birds often display a protruding breastbone. Judges often are somewhat forgiving of such problems when placing Runners within their class if the overall quality of the bird is very good, but it certainly hurts the Best Runner when competing outside the class for Champion Duck, for example. The top awards in the Runner class are often dominated by the Whites which tend to be superior in type. There are five breeds of ducks that are recognized by the American Bantam Association in the Bantam Duck class. They are Calls, Black East Indies, Mallards, Wood Ducks, and Mandarins.