Although the rules of Heraldry are quite prescribed, the fact is that the style of the crest, or coat-of-arms, is a matter of choice of the bearer. With regard to the Yarbrough Coat-of-Arms, all variants bear the same characteristics:
(1) Colors: pale argent (silver) and azure (blue);
(2) Shield: more or less traditional in shape with a chevron (upside down "Vee") between three chaplets, all counterchanged (colors swapped);
(3) Crest: a falcon close (belled gold), preying on a cock pheasant or duck (mallard) proper (normal position -- not inverted), although some renditions may show the bird inverted;
(4) Motto: [traditional]"Non est sine pulvere palma." (Literal: The prize is not won without dust.") alterante: "Nocte Volamus."("Who dares, wins.")

Thus, the depictions below are perfectly good coats-of-arms. The rendition on the right was adapted from the version used by Charles David Yarborough.