Why do horses pick up the wrong lead?

A horse that consistently picks up the wrong lead is never doing it randomly — wrong leads always have a cause, and that cause is almost always identifiable through careful observation of when the wrong lead happens, which lead is wrong, and what the horse's body is doing at the moment of the departure. The most common cause is insufficient or incorrect preparation at the moment of asking. A horse that is straight, unorganized, or bent in the wrong direction at the moment the departure cue is applied has no mechanical reason to take the correct lead — his body is in a position from which the wrong lead is equally or more available than the correct one. A rider who fixes the preparation without changing anything else about the cue frequently finds the wrong lead problem resolves itself almost entirely. Natural crookedness and physical asymmetry are the underlying reason most horses have one lead they are more reliable on than the other. Every horse is naturally stronger and more supple on one side, with one hind leg that engages more freely. The lead corresponding to the naturally stronger and more supple side will almost always be more reliably correct. Correct this through systematic development of the weaker side rather than through stronger cues on the stiffer direction. The cue itself can be the cause when applied inconsistently, too late, or with conflicting aids. A rider who applies outside leg correctly but simultaneously restricts with the inside rein or tips her weight to the outside seat bone gives the horse contradictory information — the horse takes the lead that the dominant signal suggested. Consistency and coordination of the complete departure aid package is what produces consistent correct leads. Anticipation and pattern learning produce a specific type of wrong lead problem. A horse always asked for the left lead when tracked left will begin anticipating based on direction rather than responding to the actual cue. Break up patterns deliberately — ask for the left lead while tracking right, ask for departures at unexpected points — so the horse learns to respond to the cue rather than anticipate based on established patterns. Rider position errors are frequently invisible to the rider. A rider who collapses the outside hip or drops weight to the outside seat bone at the moment of asking inadvertently loads the outside at the precise moment the inside needs to be loaded. Video of actual departure attempts typically reveals weight distribution patterns that explain persistent wrong lead problems that have resisted every other correction.