How many letters does the top answer for “the characteristic sound made by a turkey cock” have?

The most common answer is gobble (6 letters).

Crossword clue: the characteristic sound made by a turkey cock

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

gobble 6 letters wn-def

eat hastily without proper chewing

the characteristic sounds made by a horse 50% similar → neigh, nicker, whicker