Answer: greyhounds

AnswerCrossword Clue
GREYHOUNDSTrack dogs
GREYHOUNDSFast dogs (hey!) running wild in estate (10)
greyhoundsGREYHOUND, a tall slender fast-moving dog of an ancient breed orig used for coursing also GRAYHOUND
greyhoundsA dog of a tall, slender breed having keen sight and capable of high speed, used since ancient times for hunting small game and now chiefly in racing and coursing