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What To Do If Your Horse Constantly Opens Their Mouth With A Bit!

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Your horse is opening their mouth under saddle. You’ve tried to solve the problem with different bits, nose bands, and even had the vet out to check your horse’s mouth but you can’t find the source of the problem. My horse Chip had a similar issue with chopping the bit. It took me a while

Your horse is opening their mouth under saddle.

You’ve tried to solve the problem with different bits, nose bands, and even had the vet out to check your horse’s mouth but you can’t find the source of the problem.

My horse Chip had a similar issue with chopping the bit. It took me a while to find out what was causing him to react that way and find a solution.

If your horse is constantly opening their mouth with the bit. First you need to find the root cause for the behavior, which is some sort of discomfort and then you need to find a solution to make the horse comfortable.


If you haven’t read my post about WHY horses open their mouths under saddle you should first head over to that post and read it before continuing on this post.

First I am going to help you evaluate your horse with a series of “tests” to find out what the root cause is for your horse opening their mouth under saddle.

Then once you have a general idea of the cause you will be directed to a possible solution to the problem.

Riding with our horses should be fun and bring joy for both horse and rider. Not fear, anxiousness, discomfort, or pain.

So I applaud you for being proactive and doing something, so you move on to a better place with your horse.

Disclaimer: In no way should you take this advice I will be sharing over your vet’s advice. If you are having a problem with your horse make sure you have the vet help you evaluate what is going on. They have extensive knowledge and experience. I’m just an equestrian sharing what I have learned and experienced with horses in my own life and not sharing this as professional advice.

How To Determine The Root Of Why Your Horse Is Opening Their Mouth Under Saddle

Now that you’ve read my other blog post about why your opens their mouth under saddle and have a basic idea of potential causes, it’s time to figure out which one of these are creating discomfort in your horse.

 It could be one thing or it could be several. You may end up fixing one problem and then later find another problem is still affecting your horse.

Just keep being a detective and helping your horse through the problems one at a time. You will make it through this and feel so much better because your horse is happier and more comfortable.

Evaluating Your Horse For The Reasons Behind Opening Mouth While Being Ridden

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This section is just a general guide to help you figure out what may be going on with your horse.

It is best if you try out the tests as you would follow a flow chart.

The results of each test will lead you to the next test you should try until you have a general idea of what’s the problem is.

This doesn’t cover every possible cause so make sure you are involving your vet if you don’t find a simple solution.

1. Testing If Hands Are A Problem

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Be lunged on your horse by an experienced equestrian or instructor. 

Tie up your reins so that they are there if you need them but aren’t going to dangle and come over the horses head. You are going to let them rest on your horse’s neck and ride hands free. 

After warming up, be patient and get an active, rhythmic and relaxed trot. Make sure you lunge your horse in both directions. 

  • If the horse doesn’t open its mouth or chomp the bit that is a good indicator the horse doesn’t appreciate how you handle the reins. Go to test number 2.
  • If the horse does still chomp the bit then we keep searching out the problem. It is probably not just your hands and not because of contact. Because you weren’t holding reins and the horse had no contact. Go to test number 3

2. Testing To See If It’s Contact That’s The Problem Not Just Hands

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So we know now your horse was comfortable being ridden with a rider, a bit in the mouth, but without you using the reins and with no contact. So now we want to evaluate how the horse does with steady contact using side reins. 

So have your experienced lunging helper apply side reins short enough for a light consistent contact but not tight. If your horse is warmed up establish your active rhythmic and relaxed trot.

After a few laps at the trot is your horse relaxed in the mouth or chomping and opening mouth?

  • If your horse mouth is relaxed then it is very possible that the problem is with how you handle the reins. Problem Most Likely: how you handle the reins. Go to the solutions section for handling reins.
  • If your horse is chomping at the bit or opening mouth then onward we search. There are still many potential causes for this issue. Go to test number 3.

3. Check The Bit Size And Placement In The Horse’s Mouth

As you found out earlier if the bit doesn’t fit right for your horse or the bit is not placed correctly in your horse’s mouth it can cause discomfort.

Measure your horse’s mouth with a bit sizer.

If your bit is the correct width then check placement of the bit in the horse’s mouth.

If your bit is not the correct width then use a similar bit with the correct width.

Check the placement of the bit.

  • Have the horse’s bridle on.
  • Spread apart the horse’s lips on the side so you can see where the bit is sitting.
  • Is it in the middle of the large space between the front teeth, canines, and the back teeth and molars?
  • You want to make sure the bit is not going to bang the teeth toward the front or the back.
  • Now leaving the horse’s mouth alone and looking at the side of the horse’s mouth. There should be about one wrinkle above the bit.
  • Horses have different length mouths and lips and you want to make sure you are not pulling the corners of the mouth too tightly.

Repeat exercise from test number 2 with the newly fitted and placed bit.

  • If your bit size and placement were correct and the horse is chomping the bit or opening mouth go to number 4.
  • If the horse is quiet and comfortable with their mouth then the bit or placement of the bit in the horse’s mouth may have been causing the discomfort. Problem Most Likely: Bit was not the right size and or the bit was not in the right spot in the horse’s mouth. Use the bit that now fits and is placed correctly.
  • If the horse is still opening mouth and chomping the bit after adjusting bit size and placement go to number 4.

4. Testing To See If The Saddle With The Weight Of The Rider May Cause The Horse Discomfort

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We are going to do a quick check that your weight or the saddle is not what is bothering your horse and causing them to open their mouth.

Simply lunge the horse with the bridle, bit, reins tied up, and the saddle on.

The weight of the rider is gone so the saddle won’t be pressing into the horse’s back.

When a saddle fits incorrectly it can still affect a horse without the rider but an ill-fitting saddle has a much more obvious effect on the horse when the rider is in the saddle weighing it down.

Now attach side reins to the horse so there is a light contact and trot the horse both directions.

  • If the horse is relaxed and doesn’t chomp or open their mouth then that means likely something is bothering the horse with the rider on their back. Problem Most Likely: Ill-fitting saddle, back soreness, and/or weight of the rider. Go to the solutions section for sore back and saddle fit.
  • If the horse is still chomping the bit, then it is most likely something else bothering the horse. Keep searching. Go to test number 5.

5. Test If The Noseband May Be Bothering Your Horse

If you can borrow several different kinds of nosebands. Make sure they are not tight. You should be able to put at least two fingers between the horse’s face and noseband. 

Ride several different times with each of the different nosebands and evaluate whether your horse relaxes their mouth with any of them. You can also try riding without a noseband.

  • If your horse relaxes with one of these. It may be that the noseband your horse usually uses is putting pressure in an area that is uncomfortable and your horse has been reacting to it. Problem Most Likely: Noseband was putting pressure in an area the horse felt was uncomfortable. Use the noseband that worked for your horse.
  • If your horse is no better still tense and opening mouth then go on to test 6.

6. Dental Appointment- Rule Out Any Dental Issues

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Use an actual trained Equine Dentist not a Veterinarian that does dental work.

Veterinarians that do overall care may not have the expertise or finesse of an actual Equine Dentist where all their training and work is focused on dental care. A regular Vet may miss something that an Equine Dentist would not.

So set up an appointment and have the horse’s teeth and mouth checked out. Talk to the dentist about the tests you have been doing to evaluate what is going on and see if the Dentist has any suggestions, insight or ideas, to help you with the evaluation process.

Make sure you ask the Equine Dentist if your horse has a low palette and write it down so you don’t forget.

Also have Dentist check for TMJ tightness.

Once your horse is cleared to be ridden and free of dental issues. Ride your horse and evaluate.

  • If your horse is relaxed with their mouth then it is clear the problem was dental issues. Problem: Dental Issues. Make a regular schedule with the Equine Dentist to check your horse’s teeth.
  • If you find out your horse has a low palate but is now or was clear of dental issues and is chomping or opening his mouth the bit might be a problem for your horse. Go to number 7.
  • If your horse is now or was clear of dental issues but the horse is still tense, chomping or opening its mouth then it is something other than dental problems. Go to number 8.

7. Testing To See If The Bit Is Wrong For Your Horse With A Low Palate

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Now that we know your horse has a low palate, there are certain bits that horses with this kind of mouth don’t do well with. A single joint bit will bump the roof of the horse’s mouth. 

There is also less room for the bit with a low palate. A thick mouthpiece will be uncomfortable and make it hard for the horse to swallow.

Obtain several bits to try out with your horse.

Make sure the bits are double-jointed and on the thinner side but only as thin as necessary. The thinner the bit the more severe the pressure.

Ride and evaluate how your horse does with the different bits.

  • If your horse is quiet and comfortable with the mouth then it is likely the type of bit didn’t work for your horse. Problem Most Likely: Bit wasn’t the right type for a horse with a low palate. Use the new bit that works for your horse.
  • If your horse is still opening their mouth then back to searching for an answer for why. Go to number 8.

8. Test For Overall Pain By Having Your Vet Evaluate Your Horse

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At this point, there could still be pain somewhere on your horse causing this behavior.

We covered many different aspects and this may be the most expensive evaluation and test, but it is for the wellbeing of your beloved horse.

It could be that, if not pain, then your horse may be anxious, tense or fearful and needs to work on trust, relaxation, and correct training.

But first let’s rule out pain. 

Possible Culprits of Pain To Rule Out

  • Ulcers
  • Lameness
  • Muscle Soreness
  • Arthritis
  • Past Injury
  • Illness or disease
  • TMJ issues
  • Poll pain

These are quite a few things to evaluate for your vet.

If you suspect any of these problems make sure you have as much information on hand as you can to give to your vet.

Be aware if your horse is showing any other symptoms, other than just opening its mouth, or chomping the bit. 

The vet will probably do a general lameness exam, and then evaluate what they think needs to be checked.

But if you really want your horse to be checked for something you’re suspecting then let the vet know. Push for what you think is best for your horse. It might take the vet more time but you’re the one paying the bills.

  • If your horse has pain from whatever it may be. This is likely the problem. It could potentially be anxiety or tension as well but you need to treat your horse and get rid of the pain before you can be sure. Problem Most Likely: Pain from whatever source it may be. Follow your vet’s instructions and next steps to treat the problem. Re-evaluate your horse once the problem is resolved.
  • If your horse is pain-free but is still chomping the bit and opening their mouth under saddle. Problem Most Likely: Tension, Anxiety, Fear, or Lack of quality training. Look under the solutions section Anxiety and Tension.

Solutions To Get Horse To Stop Opening Mouth While Being Ridden

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In this section, I am going to go over solutions to some of the problems causing your horse to open their mouth under saddle.

Handling Reins

If you are reading this section it might be because the way you have been using your hands and handling the reins has been causing your horse discomfort. 

If this is the problem it could be because you need to work on your balance, seat, and coordination of your aids.

If you have a good seat then you need to change your mindset on how you use your reins.

If you don’t have a good seat it is possible you also don’t have a good understanding of how to use the reins properly.

You can’t have good hands horseback riding if your seat, balance, and coordination are bad.

Make sure you are working with a good riding instructor that has empathy for horses, emphasizes the basics, and is encouraging, but still provides helpful feedback.

Using Reins As A Beginner Rider

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This applies to beginner riders and riders that have not yet learned about riding with contact.

  • Hold the reins properly with thumbs on top and pinkies underneath and wrapped around the rein.
  • Hands should be closed in a soft fist (not with open fingers or tight hard fists.)
  • Your reins should be long enough you can keep your hands over the horse’s withers, with your elbows slightly forward instead of hanging down directly by your side.
  • There should be a slight sag in the reins, but short enough that if you just squeeze your fists then it puts pressure on the bit.
  • The reins should be used smoothly and gently.
  • Both hands squeezing slightly backward (like squeezing water out of a sponge) tells the horse to slow down or stop. Only use the amount of pressure needed for a response. Always start with lighter pressure and gradually increase until the horse responds. Then soften your fists to relax the pressure.
  • When squeezing on reins, if the horse is taking a long time to respond, you can try a series of squeeze and release instead of one long squeeze.
  • Keep your hands relaxed when the horse is moving forward and make sure you follow the horse’s head movement with your hands so you don’t accidentally bonk the horse in the mouth with the bit.
  • To do a wide turn using the rein, bring one hand smoothly out to the side, away from the horse to turn that direction. Squeeze the fist so the horse feels the pressure which signals to turn that direction. This is called a leading rein or an opening rein.
  • To do a tighter turn, squeeze and relax one hand several times, bringing that hand straight back. Only bring your hand back as much as is needed for the turn and remember to keep movements smooth. This is called a direct rein.
  • A neck rein is when a rein presses against the horse’s neck. It can help turn the horse or stop the horse from moving sideways. One hand moves toward the horse’s neck so the horse feels the rein but your hand should not cross over the neck. Using the outside rein can help turn the horse even when you are using a direct or opening rein.
  • Make sure you use correct leg aids along with the rein aids.

Using Reins For Riders Working On Light Contact

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This is the next step with using your reins after you have developed a balanced and correct seat. Your instructor should be able to evaluate whether you are ready to learn riding with a light contact.

  • Light rein means that all the time, you have a light, steady feel of your horse’s mouth through the reins.
  • The reins are lightly taut and should make a straight line from the bit in the horse’s mouth to your hands.
  • The rein aids changing the pressure on the bit are done by squeezing and relaxing your fingers.
  • Rein aids should look almost invisible.
  • Your hands must follow the motion of the horses head motion without losing contact, bumping, or pulling on the horse. This is known as passive contact or following hands.
  • The contact should feel the same as light and steady as the horse’s head moves.
  • Avoid intermittent contact. This sometimes happens when you get stiff in your arms or shoulders, which freezes or restricts your arms from following the horse, and every stride the horse tries to stretch their head out they feel a jerk on the bit. This teaches the horse not to stretch out and not to trust your hands.
  • To ask for a halt, stop moving your elbows and apply squeezes with your fingers to the reins without pulling your hands back. When the horse stops relax your fingers but, don’t release the contact, only reduce the pressure going back to the light steady contact.
  • When you ask for a turn apply squeezes with your fingers with one hand in the direction you want to turn. You will find that the horse responds to a lighter touch than you may have thought.
  • While trotting, make sure that your hands are steady and be careful not to let them go up and down as you post the trot or bounce as you sit the trot.
  • In the canter keep your arms and shoulders relaxed and follow the horse’s mouth with a soft gentle contact.
  • Always give your horse a break here and there from the contact by letting your horse have a long rein.
  • Make sure your horse is moving freely forward, in a steady rhythm and you are using your leg aids along with the rein aids.

Using Reins For Riders Working On Getting Horse Through/ Connected/ “On The Bit”

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This is for the more experienced rider that has the basics down for rein aids and can keep a consistent light contact with the horse while keeping the horse moving freely forward in a consistent rhythm.

If you have been heavy, busy, or rough with your hands consider going back to working on establishing a consistent quiet light contact before working on getting a horse round and connected.

  • In order to give good rein aids, your seat must be correct and balanced, and your back, shoulders, arms, and hands must be used correctly.
  • Rein aids must always be supported by the leg aids.
  • Rein aids are changes of pressure in the horse’s mouth not pulling.
  • There should be a straight line from elbow to bit.
  • The horse must be ridden from back to front. The legs asking for energy from the hind end, the seat adjusts the energy as it goes through the back and the hands receive the energy and adjust.
  • Busy hands that fidget, nag, pull, and overuse the hands without using supporting leg aids, is riding the horse front to back.
  • The contact should be going through your hands, wrists, forearms to elbows, upper arms to back and shoulder blades.
  • Light Contact- Mentioned above. The reins are straight and not sagging. There is a light consistent elastic feel of the horse’s mouth. The contact stays steady as the rider’s hands follow the motion of the horse’s head.
  • Active Rein Aid– This is the “taking” rein when your hand squeezes briefly as if squeezing water out of a sponge. There can be small changes in the direction of the pressure such as outward (opening rein), backward (direct rein), or inward (indirect rei), which creates different effects.
  • Releasing- This is when you ease up the contact by relaxing the pressure of your fingers, but you don’t drop the contact and you don’t let the reins slide through your fingers.
  • Holding Rein- This is a non-allowing resisting rein. This is to contain energy, resist the effort of the horse pulling the rider’s hands forward, or pushing their head forward. You must not pull but resist instead. The resisting comes mostly from the upper arm, shoulder blades, back, and seat and you need to stay elastic not stiffen up even if the horse is being strong.
  • Supportive Rein- This can be light rein contact, active contact, or a holding rein. Supportive rein on straight lines uses both reins while on a circle or turn the supportive rein will often be the outside rein to keep the horse from falling in or out on the turn
  • Seat aids and leg aids are the first ingredients to getting a horse on the bit. You need the horse to be responsive to the seat and leg.
  • Then the horse needs to be able to accept contact, meaning the horse’s mouth is soft, closed, and the neck, poll, and jaw are relaxed.
  • The horse comes on the bit when the horse has enough energy and engagement in response to the leg and seat. The horse needs to also trust and be relaxed with the rider’s hands.
  • When the horse is truly on the bit the withers raise, the neck arches as the poll comes forward, the horse reaches forward to take a steady contact with the bit, flexing at the poll and face will come closer to being on the vertical. The back is lifted and springy.
  • When a horse is truly round lifting their back, it feels much different than when the horse’s back is hollow. Lifted the horses back feels more supple and swinging whereas hollow the horse’s back feel more rigid and stiff.
  • Stretching down also known as “chewing the bit out of the rider’s hands” or stretchy trot if at the trot… is an exercise that can improve contact, roundness, and relaxation. This teaches the horse to seek out the bit, relax their back, neck, and poll. It is also a confirmation of good contact. This is a good exercise to use in warming up and at the end of a ride to allow the horse’s muscles to relax and stretch.

Ill-Fitting Saddle And Sore Back

You can do a basic check of your saddle fit on your own to get a basic idea if your saddle is decently fitting or severely off. However your horse would greatly benefit from a Professional Saddle Fitter to come out and evaluate your horse. 

Improper saddle fit can sometimes be hard to see if you are not well trained or experienced for what to look for. An article how to fit a saddle can only help so much and saddle fit affects a horse tremendously.

It is better to ride with a bareback pad than an ill fitting saddle. If your saddle has not been fitting properly then your horse is probably experiencing back soreness. It’s like running for an hour with shoes that are uncomfortable and don’t fit, with a 20lb pack on your back.

Another problem that can cause back soreness is if you are too heavy for your horse. If you are too heavy and the saddle doesn’t fit well the pain will be greater. 

Find out if your horse is the right size for you.

Anxiety And Tension

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If you are here then the problem is most like the horse is anxious, nervous, fearful, anticipating, tense.

This is not a quick fix. But there are things you can do to help your horse become more relaxed, confident and trusting.

Make sure that you are in the right mindset of patience. Your horse needs lots of love, encouragement, and to feel safe.

I know some of this sounds kind of hippie like but it’s true.

Start on the ground. Work on getting your horse to trust you. Take your agendas off the table and just enjoy your horse as a buddy and companion sometimes.

When I say agenda I mean the plans you have for your horse all the shows, deadlines, goals. Just be with your horse at this time, not thinking about those things.

  • Hand graze your horse.
  • Groom your horse just to groom no riding.
  • Try groundwork like the 7 games with your horse.
  • Go for walks like you are walking a dog instead of trail riding you are walking next to your horse.
  • Bring your horse treats if you don’t want to hand feed that is fine. Horses are often very food motivated.
  • Look into clicker and target training. That is known to be good for confidence building.
  • Be creative and have fun with your horse. Be blessed by the awesomeness of your horse and that you can have companionship with them.

Under saddle once again let go of your agenda, because with a tense anxious horse that is not going to help. Feeling like you have to reach that next goal. Keep improving and pushing forward.

You may need to relax yourself back up a bit and be at your horse’s level. Once you have your horse relaxed, trusting, and happy then you can focus on your goals again. But get both you and your horse on the same page first.

So under saddle think more experimental, be patient with your horse, don’t be afraid that you will make mistakes or not look totally together and perfect and just stay hopeful that you and your horse will eventually get it.

  • Try working on communicating with your seat and legs more and reins less.
  • Work on your contact, smooth soft movements with the bit and keeping the bit steady in your horse’s mouth.
  • Try riding in a bitless bridle and see how your horse responds. If the bit makes your horse tense this may be a good alternative to helping your horse relax.
  • Try smallish circles when you feel your horse getting tense and work on keeping your hands real steady, supportive, consistent.
  • Follow your horses head to keep the rein pressure consistent but don’t force the horse into a frame. Think that your horse needs to relax into the frame and it may not happen for a few rides if they were always used to heavy pressure, seesawing, pulling and releasing on the reins. 
  • Be your horse’s safe place.
  • Reward your horse often with scratches. There was a study done horses respond better to scratching on the neck than patting. 
  • Go on walk hacks with a loose rein, and just enjoy the time together. Even let your horse relax and just eat grass if you have a bitless or hackamore. 
  • Try doing ground poles to change up your routine and to get your horse focused on something other than what to do with their mouth.
  • Give your horse lots of walk breaks with a long rein.

These are just some ideas to help relax a tense horse. There are many more ways. So if you know of more ways please share in the comments!

Few Quick Points About What To Do When Your Horse Opens Their Mouth Under Saddle

  • Bear in mind that there can be more than one issue causing your horse to react with an open mouth, chomping at the bit or similar behavior under saddle.
  • Even if it seems hard or like you can’t find the source of the problem right away keep being a detective and searching out the root cause. In the end it may be that your horse is tense, fearful or anxious.
  • Once you are able to work through the problem and your horse is feeling better and working without pain or tension. Your horse will be happier and healthier and you will be happier because you want the best for your horse.

Do you have a horse that chomps at the bit, opens their mouth under saddle, sticks their tongue out or grits their teeth.

Tell us about it in the comments!

Hang in there your horse is worth it and it will be so nice when they’re happily going along able to relax into the bridle.

Cheers, Kacey

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Disclaimer Notice: Please be aware that horseback riding and related equestrian activities carry inherent risks. The advice and experiences shared on this blog are for informational purposes only and are not a substitute for professional training or advice. Ensure your safety and that of your horse by wearing appropriate gear, practicing safe horse handling, and consulting with certified equestrian professionals. Remember, each horse is unique, and techniques may vary accordingly. Always prioritize safety, respect, and patience in your equestrian endeavors.

Kacey Cleary Administrator
Kacey has been an equestrian since 1998. She was a working student at several eventing and dressage barns. She has owned horses, leased horses, and trained horses. Kacey received an A.S. in Equine Industries from UMass Amherst, where she rode on the dressage team. She was certified with the ARIA and is licensed to teach riding in MA. She has been a barn manager and has run her own horse farm.
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