A person or creature that thumps their craw; possibly a dialectal or playful term for a rooster or bird that puffs out its chest.
From 'craw' + 'thump' + '-er' (agent suffix). This appears to be a compound word combining animal anatomy with onomatopoeia, possibly regionalism.
This is the kind of marvelous compound word that real people invented for rural animals—like calling a rooster a 'crawthumper' because of how it puffs and thumps its chest when crowing!
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