E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
To show the white feather. To show cowardice. No gamecock has a white feather. A white feather indicates a cross-breed in birds.
Showing the white feather. Some years ago a bloody war was raging between the Indians and settlers of the backwoods of North America. A Quaker, who refused to fly, saw ne day a horde of savages rushing down towards his house. He set food before them, and when they had eaten the chief fastened a white feather over the door as a badge of friendship and peace. Though many bands passed that house, none ever violated the covenant by injuring its inmates or property.