Softening the Hard Mouthed-Horse

Softening the Hard Mouthed-Horse

Horses develop a hard mouth for many reasons, including pain, stress, and learned behavior.

Photo: iStock

Q. I bought a horse at auction with an unknown training history. When I rode her, I found that she’s saddle broke but has an incredibly hard mouth when ridden in a snaffle. Any time I put pressure on the reins, she responds by pulling 10 times harder. She’s difficult to steer and stop, and don’t even think about trying to “collect” her or set her head. What can I do to soften her mouth and make her more responsive?

A. Horses develop a hard mouth for many reasons, including pain, stress, and learned behavior. To resolve the problem, consider each possible cause, starting with pain.

Is your horse experiencing discomfort or pain?

A veterinarian can determine if your horse’s resistance to rein pressure is due to pain. Checking the oral cavity is an obvious first step; a problem as simple as sharp points on the molars can lead to painful ulcers of the buccal membranes (the inside lining of the cheeks).1,2 Poorly fitting tack can also cause discomfort. A bit that doesn’t fit properly can cause bruising and ulcerations on the bars and corners of the mouth,2 and a tight noseband (sometimes used to prevent the horse from evading the bit) can impede breathing and cause bone microfractures.1

Tack-fit issues should be evaluated by a veterinarian or experienced trainer, who can make informed recommendations about equipment (for example, trying a bitless bridle or different bit). In general, avoid using mechanical devices, such as a severe bit, draw reins, or martingale, which may offer a short-term solution but won’t ease discomfort or teach the horse to respond to a light hand.

Is your horse anxious?

An anxious horse is more likely than a relaxed horse to ignore rider cues. Anxiety can be triggered when a horse is worked in a new location, is around unfamiliar horses, or is ridden by a new or inexperienced rider. If anxiety is an issue, give your horse plenty of time to adjust, and start with basic exercises at the walk—more challenging exercises will only amplify problems.

A horse might also become anxious if expectations for performance and “collection” exceed its level of training and conditioning. When forced into hyperflexion (also referred to as “rolkur”) horses show signs of stress3 and their movements appear rigid and choppy.4 Softening your hands and letting the horse stretch its neck can help.

Has your horse learned to be hard-mouthed?

Horses learn to stop and turn through the release of rein pressure. Constant tension, without release, will teach a horse to become hard-mouthed.5 The problem might begin innocently enough: The rider applies rein pressure, and when the horse fails to respond the rider increases the pressure, or bumps and saws on the mouth, waiting for the horse to slow down or turn.

This heavy-handed “tug-of-war”4 is a futile game; if the pressure is constant or increased, the horse will learn to evade the bit, ignore rein cues altogether, or respond only to heavy pressure. On the other hand, if the rider releases the rein pressure while the horse is still pulling against the bit, then resistance will be rewarded. Instead of repeating the same ineffective pattern over and over, set the horse up for success by structuring situations where the horse yields—even slightly—to a light rein cue that can be rewarded with a release of pressure, and then build from there.

Take-Home Message

Horses become hard-mouthed for various reasons, and professional help is often needed to resolve the problem. A veterinarian can recognize and treat causes due to pain, and an experienced trainer can develop greater sensitivity and responsiveness in both the horse and rider.



  • 1McGreevy, P.D. (2015). Right under our noses. Equine Veterinary Education 27(10) 503-504.
  • 2Tell, A., Egenvall, A., Lundström, T, and Wattle, O.  (2008). The prevalence of oral ulceration in Swedish horses when ridden with bit and bridle and when unridden. The Veterinary Journal 178, 405-410.
  • 3van Dierendonck, M., van Dalum, M., Beekmans, M., Christensen, .W. (2012). Acute stress responses of dressage horses ridden in three different head and neck positions. 8th International Equitation Science Conference Proceedings.
  • 4Heuschmann, G.. (2009). Tug of War: Classical versus Modern Dressage (revised edition). Trafalgar Square Books.
  • 5McLean, A.N. (2005). The positive aspects of correct negative reinforcement. Anthrozoös 18(3) 247-254.

About the Author

Robin Foster, PhD, CAAB, IAABC-Certified Horse Behavior Consultant

Robin Foster, PhD, CAAB, IAABC-Certified Horse Behavior Consultant, is a research professor at the University of Puget Sound in Seattle, Washington, and an affiliate professor at the University of Washington. She holds a doctorate in animal behavior and has taught courses in animal learning and behavior for more than 20 years. Her research looks at temperament, stress, and burn-out as they relate to the selection, retention, and welfare of therapy horses. She also provides private behavior consultations and training services in the Seattle area.

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