Why we shouldn't be using muzzles to prevent our dogs from chewing
When a dog starts destroying household items that are expensive or hold sentimental value, it is often considered inappropriate. But this may be dependent upon the humans expectations, as some may not be concerned about the occasional spontaneous shoe explosion. However, chewing becomes of particular concern when the items can harm them, such as electrical cords, toxic plants, or sharp objects. This behaviour is increasingly concerning if the dog is or is likely to ingest the items that it chews.
In addition, if a dog repetitively chews objects to the point where it interferes with their daily routine, such as eating, playing, sleeping, or interacting with people, it may be indicative of compromised welfare. Some dogs may develop destructive chewing habits because of feelings of stress or boredom.
A dog chewing inappropriate items can sometimes be indicative of an underlying medical condition. There are several medical conditions that can lead to increased chewing behaviour in dogs, such as dental problems, gastrointestinal issues, nutritional deficiencies, and allergies.
When a dogs chewing is considered inappropriate It is important to consult with a qualified, ethical professional such as a veterinarian and/or Behaviourist to rule out any potential medical causes for the behaviour and to develop an appropriate treatment plan. 
Muzzles are a great tool to help aid training in many contexts, such as dog interactions or vet trips. Muzzle use is appropriate if the guardian is going to be present, the muzzle is well fitting, and the dog is properly conditioned to wearing a muzzle in advance. Many will choose to utilise a muzzle as they continue to progress through a training plan, which can include prevention of ingesting dangerous items, or to prevent chewing, when supervised, in the short term - alongside a comprehensive plan written by an ethical canine professional.
However, muzzles should not be used to inhibit a dog from performing a natural normal behaviour – unless that behaviour is putting the animal at risk, and then the muzzle would only be appropriate as part of a wider training programme and the dog never left unattended.
Inappropriate Chewing, such as when the dog is home alone, is likely an attempt to feel better. By placing a muzzle on the dog, it will prevent them from being able to chew, but it won’t stop the dogs need to chew.
If the dog is using chewing as a coping mechanism for feelings of frustration, anxiety or boredom and we don’t provide them with that outlet, there is a risk that the dog will find other inappropriate coping mechanisms and it is likely that once the muzzled is removed, the chewing will continue or may even cause the chewing to escalate further.
There are a wide variety of compelling reasons as to why we shouldn’t muzzle a dog to prevent chewing, but particularly without a guardian present.
For example, the dog may start to panic, attempt to remove the muzzle, or begin chewing the muzzle itself. Without a guardian to remove the muzzle, this could potentially lead to the dog injuring themselves.
- This could involve them using their paw to try and remove the muzzle, which may lead to them getting a claw caught and causing damage to their claw, paw, and mouth.
- The dog could move their head around excessively to remove the muzzle. This could lead to a strain in the neck and back area if this took place for extended periods of time.
- They could rub their muzzle against objects, getting the muzzle caught which could in serious cases lead to strangulation. In less serious cases could result in facial irritation, hot spots, or sores.
- The dog may chew and ingest parts of the muzzle itself which could have medical implications.
The risks of using a muzzle to prevent chewing increase further if the muzzle is poorly fit and doesn’t allow the dog to perform vital behaviours such as chewing, drinking, and eating.
And finally, a dog could be chewing excessively due to pain or discomfort. Ignoring this might lead to further medical implications as well as continued compromised welfare. 
Placing a muzzle onto a dog to prevent chewing is ignoring why a dog is chewing, and there are many potential motivating factors to consider.
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If a dog is chewing when a guardian leaves the home, chewing may be an attempt to reduce stress and help relieve anxiety, which could result in further distress if the dog is then muzzled an unable to self sooth. In addition, the dog may learn that the muzzle is a pre-curser to being left unattended which is likely to cause negative associations with the muzzle rendering it unusable in the future alongside not helping to change the way that the dog is feeling when they are left.
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If dogs are chewing due to feeling under-stimulated or bored and we muzzle them, we are limiting their access to appropriate outlets, which could lead to increased boredom and potentially even barking as their physical and mental needs continue to be unmet.
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Chewing can be a displacement behaviour if a dog is feeling frustrated. Placing a muzzle on a dog who is chewing due to feelings of frustration is likely to cause further frustration, because they are no longer able to access something they needed to help regulate their emotions. Which may result in other frustration related behaviours such as barking, jumping, restlessness, pawing, scratching or even continued and more vigorous attempts to chew – either with the muzzle on, or once the muzzle comes off.
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We also may inadvertently cause a dog to feel frustrated when they weren’t previously by adding a muzzle and their expectations of being able to pick up, chew or carry objects no longer being met. Or alternatively frustration caused by a new lack of autonomy, due to feeling stuck or trapped in a muzzle that they themselves cannot remove.
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Some dog’s love to chew and explore with their mouths more than others and find it fun. Age should be taken into consideration, and it is normal for puppies and adolescent dogs to use their mouth to explore the world. By preventing exploratory behaviour or not providing alterative safe outlets, we are thwarting learning opportunities and potentially missing indicators that our dogs are feeling unfulfilled.
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If a muzzle is not properly conditioned and fit, or the dog feels that there is no way out of their current situation (in this case, out of the muzzle) they may not feel they are able to perform normal dog behaviours. As a result, the dog may experience ‘learned helplessness’ where they no longer attempt to perform normal behaviours, which could result in the dog not feeling comfortable enough to move, drink or eat.
- Alternatively, behaviours may be temporarily suppressed, but reoccur later either in the same form such as increased intensity of chewing once the muzzle is removed, or in other inappropriate ways such as chewing is perceived as no longer available and therefore begin jumping, grabbing, and mouthing once the muzzle is removed.
Additionally, dogs may or may see a muzzle being placed on as punishment, especially if there has been no previous muzzle training and the muzzle only appears when chewing starts. The consequences of a dog feeling uncomfortable in a muzzle particularly if it is continuously forced upon them, is that they will become fearful and avoidant of the muzzle. There may be increased sensitivity around the head and neck area. Which may lead to further issues if the dog were to need their ears, eyes, neck area to be examined and receive future medical treatment such as eye or ear drops, kennel cough vaccines or oral health checks. Fear or dislike of the muzzle may also impact your ability to use a muzzle again in other contexts which could mean you are unable to get one on in a legitimate situation such as a medical emergency.
And finally, arguably most importantly, inappropriate muzzle use could result in a breakdown in the relationship between dog and guardian, which can result in more challenging behaviours to navigate moving forwards. 
AUSTRALIA
Pet Professional Guild Australia
IAABC *LIMA based approach, please research to check trainers with this accreditation are force-free*
EUROPE / SOUTH AFRICA
IAABC *LIMA based approach, please research to check trainers with this accreditation are force-free*
UK
USA
CCPDT *LIMA based approach, please research to check trainers with this accreditation are force-free*
Additionally, if you have concerns that there might be an underlying medical cause, or even if you feel there is a possibility, consult a with a veterinarian to determine if there is any physical pain or discomfort that might require treatment.
Your trainer or behaviourist may also advise you to:
Dog-proof your home: to avoid rehearsal of chewing inappropriate or dangerous items. For some dogs this is easier than others. For example, a prolific shoe chewer might benefit simply from the shoes being removed from the hallway, whereas a dog that’s chewing skirting boards or doors may need a more extensive behaviour modification programme – which should always be carried out with a force free behaviourists support.
Make sure their needs are met: a dog that feels unfulfilled is more likely to express unwanted or undesirable behaviours. Ensure that they have had adequate mental and physical stimulation, considering age, breed and individual preferences. Some dogs might need more exercise, others might need more human contact time, whereas others might need more sleep.
Increase Enrichment: outlets for chewing behaviour (such as long-lasting chews / boxes / variety of toys / interactive food toys that are appropriate for the dog's size and breed). But please note, when giving the dog enrichment this should be done with the guardian present initially to ensure that it is both safe and enjoyable for the dog and the guardian should assess which enrichment the dog loves to do. Enrichment should be easy for the dog to do initially; it should not be too difficult as this could lead to frustration.
Look for triggers: a really great way to get a head start with your trainer or behaviourist is by being able to track and recognise triggers for inappropriate chewing. Such as people walking by a window or someone leaving the home and where possible these triggers should be reduced or removed completely initially and re-introduced later with the support of your force free professional.
Limit alone time: particularly in the case of dogs that exhibit separation related behaviour, or we believe chewing to be associated with distress when left unattended, we may need to reduce or remove time spent alone in the short term. A dog walker sitter or walker could be useful and helpful to help break the day up for the dog while you are working with your trainer.
Teaching skills such as drop and leave: two useful skills that might help you better manage what you dog is chewing and prevent accidental ingestion due to humans applying pressure to drop or leave an item causing the dog to swallow in order to not loose it.
That said, there are some very extreme cases where muzzles may be used to prevent chewing – so we also ask that you remain non-judgemental if someone says that they do. There are some serious, challenging, complex reasons that a guardian or trainer may resort to muzzling in an attempt to prevent chewing, but this should only be done upon the recommendation of a qualified ethical professional.
For example, if a dog’s life if in danger, such as chewing which results in self-injurious behaviour, the dog is recovering from a surgery to remove a foreign object and a second surgery is not possible, a dog has a severe medical condition or a dog that has a history of ingesting poisonous or hazardous items.
And even in these few extreme circumstances, the dog should still have a guardian present, and the muzzle be appropriately introduced and well fit.
