This dog don't hunt

What is the origin of "this dog don't hunt"?

It's modelled on the 17th-18th century phrase "that cock won't fight". In the days of cock-fighting, a cock that wouldn't fight when out into the pit was a natural metaphor for a plan or theory that simply wouldn't work. A similar sporting metaphor from horse-racing is used when we say that a plan or theory "isn't a runner". (VSD)

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