The word racehorses 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: 15
Highest Scoring Words With Friends™ Play In The Letters racehorses
:
Seven Letter Word Alert: (37 words)
acerose, archers, careers, cashers, chaoses, chasers, coarser, coherer, coheres, crasher, crashes, crasser, creaser, creases, crosser, echoers, erasers, hearers, hearses, hoarser, rashers, reacher, reaches, rearose, rechose, recross, rehears, rescore, reshare, reshoes, reshore, roaches, scarers, scorers, sharers, shearer, soarers