Before revision: Eating crow is of a family of idioms having to do with eating and being proven incorrect, such as to "eat dirt", to "eat your hat" (or shoe), or to place one's foot in mouth; all probably originating from "to eat one's words", which first appears in print in 1571 in one of John Calvin's tracts, on Psalm 62: "God eateth not his words when he hath once spoken".
After revision: Eating crow is of a family of idioms having to do with eating and being proven incorrect, such as to "eat dirt", to "eat your hat" (or shoe), or to put one's foot in mouth; all probably originating from "to eat one's words", which first appears in print in 1571 in one of John Calvin's tracts, on Psalm 62: "God eateth not his words when he hath once spoken".