The most notorious of these was Templeton Rye: Said to be from Iowa, it was purportedly distilled using a Prohibition-era recipe that was a favorite of none other than Al Capone who, according to legend, called it "the good stuff." The story turned out to be such a load of horsefeathers that Templeton was found guilty of deceptive marketing, and forced by a judge to issue partial refunds to its customers.
Long hair on lower legs of a draft horse (e.g., Clydesdale), especially the rear legs.
In summary, the record establishes that to produce horsefeathers one starts by sawing a log (longitudinally) into boards or planks, which are then likewise center resawn (longitudinally); that the original boards, as well as the center resawn boards, have at least two approximately parallel longitudinal sawed surfaces; that the resawn boards are simply resawn again longitudinally at an angle or bevel to produce horsefeathers; and that the only other sawing required is the crosscutting of the boards to length.