Before revision: Eating crow is of a family of idioms having to do with eating and being proven incorrect, such as to "eat dirt" and to "eat your hat" (or shoe), 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 ,or to place one's foot in mouth; being proven incorrect, such as to "eat dirt" and to "eat your hat" (or shoe), 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".