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Instructor audio file (17 min)

Selecting Adult Service Dog Candidates

Whether a dog will be an acceptable assistance dog in public over the long term is dependent on many varying factors.

Since there is no consistent definition of ‘success’ for either owner-trained or program-trained assistance dogs, any statistics are general indicators at best. Success rates for shelter dogs becoming Assistance Dogs is between 5%-15% for one program.  Program-trained Hearing Alert Dogs from shelters from one facility had up to up to 31.5% success rate. Hearing dogs need to be more active and alert and a wider variety of breeds were typically accepted. The best success rates for the hearing dogs came from mixed and purebred lap dogs (companion breeds), spaniels, and terriers.

Comparatively, as discussed before, specifically bred guide dog puppies had a success rate between 50% and 80% for another program. 

There are no statistics available for success rates of owner-trained assistance dogs. We do know though that many owner-trainers have multiple dogs since several prospects have been removed from training or service in their prime due to health or temperament issues. Sources of their dogs are both from breeders (of varying reputation) and shelters/rescues. 

If starting with an adult dog sounds like a better option for you in your situation, there are some foundation desirable characteristics to look for and others to avoid in adult dogs. Since shelter and rescue dogs have unknown health histories, have serious candidates X-rayed for hips, elbows and do other health tests typical for the breeds to rule out those types of problems before accepting the dog as a candidate. These tests may be done when you have them reproductively altered, typically around 2 years of age.

Here is an article that will be of interest that compares data for purebred with mixed breed dogs. 

Desirable Characteristics of a Service Dog Candidate

These are the key characteristics for an adult service dog to have.

Once a dog is an adult, about 18-24 months old,  the temperament is pretty much set. While behaviours can be changed, the temperament drives the underlying response to situations. Adolescent dogs (6 mos to 17 mos) with an unknown social and environmental background are hard to tell what they are and what they may become. They may be in the middle of a fear period or may not. Additionally, transitioning homes during fear periods is very hard on most dogs and can affect the development of their temperament. That is why we want to consider only dogs that are 18 months to 3 yrs. In general, dogs under 3 years old will be able to provide a duration of service that is reasonable for the amount of training that needs to go into a dog to become a service dog. In some cases, you may consider dogs unto 5 years of age. More on that below.

  • adaptable to many different situations and expectations
  • confident-has low level of stress as the job as a service dog can be stressful
  • friendly and approachable-with kids (not just tolerant as you never know when a child might run up and fling her arms around the dog), adults, men, seniors but not overly friendly as you need the dog’s focus to be on you
  • dog who is good at social interactions in general
  • polite, dog asks before doing a behaviour rather than just pushes way into it
  • good body awareness for where her body is in space (not knocking into things, people) called proprioception
  • be food or toy motivated or both for training
  • wants to interact and be with people
  • low to medium exercise needs (unless you lead an active lifestyle)
  • forgiving if you accidentally run over his feet with a wheel, bump into him while walking, or an ear, foot, or flank gets pinched or squeezed
  • resilient- bounces back quickly after a scare or correction, quickly meaning a few seconds
  • social with other dogs (polite but not overly interested)
  • good with cats and other animals as they are found in many public locations
  • low to no prey drive easy to live with
  • inhibited bite when in play-a soft mouth is ideal
  • tolerant to loud sounds like thunderstorms, gunshot, fireworks (must have been introduced when young) 

Additional skills
loose leash walking is a bonus as it can be a long haul to retrain this in some dogs

Rule out health issues: 

  • joints: knees and elbow, hips
  • eyes
  • deafness
  • severe allergies
  • bowel issues
  • bladder incontinence or withholding urine
  • chronic ear infections, skin issues

Unacceptable Characteristics of a Service Dog Candidate


  • moderate to severe behavioural issues (you do not want to take on a rehabilitation project)
  • fearful, shy dog that startles/snaps when woken up or growls when disturbed when resting
  • aggressive/territorial/protective (is wary or stiffens when strangers approach handler)
  • dog that do not tolerate people in their personal space
  • overly social-jumping excessively, over-excited
  • high prey drive for cats, small animals, birds, small dogs
  • dog that takes a while to recover from incidents (not forgiving of toes being stepped on etc)
  • over-reactive to such situations
  • fearful/very uncomfortable around children
  • reactive (pays much more attention than is normal or suitable for the situation to sounds, sights, smells, movements of people, other dogs, bikes, cars etc) These dogs often scan the environment constantly
  • dog that barks often (whether excitement, protection etc)
  • noise/sound sensitive (electronic sounds, loud booms, thunderstorms) -be wary of dogs that have been on e-fence system as they have a high chance of being afraid of electronic sounds.
  • nervous dog
  • uninhibited bite during play, unaware of where mouth is or own strength
  • dogs with poor work ethic-want a dog eager to do something for us
  • low interest in training
  • personality conflict with handler for example dog enjoys physical contact and the handler does not 
  • too active for handler's lifestyle
  • too intelligent for handler to live with
  • is a wolf or coyote mix

Assessing Dogs for a Career as a Service Dog (1 hr 19 min video)
This video includes a preliminary test for a shelter dog.

Here's another video:

One Reliable Dog Assessment Test

One of the more reliable tests that has so far stood up under repetitious research is based on the dog’s response to environmental stimuli. It is called the ‘CARAT’ Clothier Animal Response Assessment Tool and was designed by Suzanne Clothier. It is not so much a temperament test as it is a way to “categorize(s) behavior traits in multiple components that are intuitive and practical”. 

If you happen to be lucky to live near a CARAT evaluator, it is worthwhile to pay the cost of having them evaluate a potential puppy or dog. Best to rule out an unsuitable candidate sooner than later.

Other so called 'temperament tests' are only good for that moment in time when a pup is tested, since dog temperament and learning is affected so much by the environment he lives in and he is shaped by experience. The tests done when the puppies are still with the litter (see the Selection of a Reputable Breeder lecture) are especially non-predictive of future temperament according to research, even if they are done by knowledgeable experienced people. If the tests are used, they must be reassessed periodically to see how the pup has changed. Even just simple learning can significantly change the outcome in a few days time.

What the test WILL do is to help you rule out dogs as candidates as they will show undesirable behaviours such as fear or aggression. If any of these appear, stop testing as the dog is not a suitable candidate and the tester risks getting hurt.  

The more simple temperament tests start to have more ability to predict the future adult dog if they are done at 18 months, once the dog’s temperament is set for life. It is always a good idea to hire an experienced local behaviourist or knowledgable positive reinforcement trainer to help you evaluate a potential candidate and the environment he is coming from. A third party who is not emotionally involved may see what you miss. This person can save you much heartache as well as time, cost and energy.

If you are considering a dog that is far away from you, definitely hire an unbiased dog professional to check out the dog, and the seller, adopter as well as the environment the dog is in.  Whether you or someone else interacts with the dogs, video tape the interactions and take notes about the interactions to refer to later. You’ll get a different perspective (more enlightening) from the video than you do in person. It's more objective.

Knowing how to read dog body language will help significantly.
Donna offers an online self-study class 
“Dog as a Second Language” through Fenzi Dog Sports Academy. Registration is open at any time for this class. 

Where to Get Adult Dogs

1. Family, friends and neighbors. You best bet is to get a good dog from a known source before it gets re-homed or given to a shelter or rescue organization. 

2. A re-homed dog by an unknown person. A dog still in its first home may be an option if you are good at evaluating people and their motives. Ask many questions. Read between the lines of their answers. What are they not saying?  If there is any pressure to adopt (like time deadlines) this is probably not the dog for you.

3. Guide dog programs: A dog that has been removed from a guide dog program may make a good assistance dog, depending on what it has been removed for. 

4. A reputable breeder may need to re-home a dog if it doesn’t turn out to be as successful as hoped in the show ring or has been retired as a champion. They may also have breeder available that only had one litter and they decided not to breed it for some reason. They may occasionally have adult dogs returned to them for a variety of reasons from illness or death of the owner and other unforeseen circumstances that has nothing to do with the dog. A dog up to 5 years of age may be suitable for small to medium breeds, especially if they already have significant training. For larger breeds that don't live as long you want a dog up to about 3 years old to maximize the working life of the dog.  The great thing is that the dog’s health and social history will be known and many of your questions will be able to be answered. 

5. Breed-specific Rescues who foster dogs in homes of volunteers. These may be responsible breeders who are taking on dogs of the same breed that are not their own or they may be volunteers who are interested in supporting dogs in need of a specific breed.

6. Dogs that have been fostered for a long period of time in a home environment (at least one month) and the foster families have had a chance to see the dog interact in public. They may be pure or mixed breeds.

7. Prison programs train shelter dogs the basic behaviours and get to know them over a period of time.

General Pointers

Ask if you can take the dog on a trial period for up to three months to see if the dog might make a good candidate. It can take several months to see the dog's true temperament come out in a new environment and to develop a bond. Most dogs don’t generalize behaviours easily (both good and bad) to new environments so this is why we often see unwanted behaviours take awhile to resurface. If the environment changes, the behavior changes. If the environment provides a situation similar to when the unwanted behaviours appeared, then the behaviour will likely reappear.

Here is an assessment to have the dog's current primary caregiver fill out honestly. This will give you an idea of the level of impulse control the dog has. I have made a pdf version of just the the test for you to print off and give to the dog's primary caregiver. Ideally have them fill it out but even if you ask them the questions, it will provide some useful information about the dog's behavior. Check out the Homework 3 section for the pdf link.

One other key piece of information to get (if you can) is who the dog's primary caregiver was. (Female, male, adult, senior etc). This is important since some dogs will bond more quickly and easily to a person of the same sex or age as their previous caregiver. Some dogs will not bond with or be willing to work for a person that does not fit that description or at the very least it can take a long time to do so.

Where to Avoid Getting a Dog

Be wary of people rehoming their dogs on internet classified ads. They often will omit key information and their interpretation of what makes a good assistance dog and what actually does, may be two different things. They may just want to foist a dog off on you so you take responsibility for it (not their problem anymore and they don’t care what imposition it is on you). It also sounds better to friends and family when they re-home a dog to a working dog home. 

Avoid puppies or dogs who were raised in or spend considerable time outdoors in kennels, yards, barns or on tie outs etc. These dogs have not developed enough people social skills or exposed to enough human-related activity, sounds and objects to easily be able to transition to lives with public access.

Avoid dogs that have not been socialized to kids, teens, seniors, other animals, small animals such as other small dogs, rabbits, cats etc. unless they have a very gentle temperament. If the dog already has history of chasing other animals, rule it out.

Avoid dogs that were sick as a puppy. If they survive Parvo or other gastrointestinal disease, this is not the dog for you. If the pup had to be bottle fed from early on or didn't thrive well. You are looking for a dog that had a healthy and functional start to life.

While some shelters have excellent programs to identify potential service dogs, many have no knowledge of what characteristics are needed. Some are just desperate to get the dogs out of the shelter and into a home. A dog in a shelter behaves very differently than one in a home or in public. A shelter is a very stressful place. Think of how your behaviour is different in a class with 100 other people than when you are at home.  This is not to say you can’t find a potential candidate in a shelter, it is just not very likely and you must be willing to take a huge risk and bring in expert help to find that dog. Refer to the service dog success statistics cited in the introduction of the lecture.  Make sure the shelter will allow you to return the dog for up to 6 mos in case s/he turns out to have health or behavioral issues that will impact his/her ability as a service dog. Of course, with shelter dogs, there is usually no access to health history of the parents so health testing of the dog’s hips, elbows and other health issues etc at the appropriate age (typically around 2 yo) is the only way to know how healthy a dog actually is. For example, a vet cannot tell if a dog has hip displaysia or not just by looking. A proper X-ray from a specific angle is needed. 

You can eliminate shelters and rescues that do not assess the dogs before adopting them out.  
Also, in low volume shelters it may take a very long time to see a potential candidate come through. 

Here is a link to an article that compares reputable vs bad rescue organizations (brokers or McRescues).  

Avoid dogs from First Nation (Indian) reservations, former street dogs and dogs rescued from meat farms as they lack the early positive socialization to humans and changing environments needed to the outside world. They often have an underlying fear of humans, of being confined on leash and may be reactive to sounds and movement. 

Avoid dogs being brought in from other countries. Little is known about these dogs (pure or mixed breeds) and it is a huge risk to think one will work out as a service dog. Some of these dogs will be street dogs and skittish at best. That cannot be trained out of them, nor loved out of them. They have not had sufficient positive socialization to people within the narrow socialization window. Typically you will only get to see a photo of the dog before you receive him. Many of these dogs have had no health testing or temperament testing. Being seen by a general veterinarian and getting vaccinated tells you nothing about his physical suitability for the job or overall health unless specific blood tests and X-rays are done (such as for hip dysplasia, etc).

Avoid dogs that have been spayed or neutered at a young age (weeks to months old). Many breeds (Golden Retrievers, Labrador Retrievers, German Shepherd Dogs and others) may be negatively affected when they are spayed under 18 mos or neutered under a year when their hormonal system that regulates their metabolism and growth is removed. Effects can be both on behaviour and health/structure. 

Here is a long term study by UC Davis in 2020 that looks at 35 breeds and recommendations of the age that each breed can be safely spayed and neutered. 

Take a look at the simplified chart