The word weathercock is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 26
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (27 words)
accrete, catcher, cheater, checker, cracket, cracowe, crochet, hectare, hoecake, hotcake, octarch, reawoke, recache, recatch, recheat, recheck, reteach, retweak, rewatch, teacher, trochee, tweaker, watcher, weather, whereat, whereto, wreathe