Ancillary K9, Denver's premier dog behavior expert, transforms challenging behaviors with personalized, intensive training. Our certified trainers address aggression, anxiety, and obedience issues. Clients see rapid, lasting results, often within six sessions. Our programs empower you and your dog for long-term success. With our Lifetime Training Assurance, we guarantee free retraining if your dog regresses. Offering private training and 24/7 support, we help rebuild harmonious relationships.
Training & services
Training goals
Behavior consultationProgram details
Expert training to address unwanted behaviors such as anxiety, reactivity, or aggression. We create customized plans to correct issues, build positive habits, and improve your dog's overall behavior, ensuring a happier and more balanced companion.
Comprehensive training designed to address complex behavioral issues such as anxiety, reactivity, and aggression. Tailored to your dog's unique needs, this program focuses on lasting solutions for a well-balanced and well-behaved companion.
Effective behavioral modification for dogs with anxiety, fear, reactivity, or other challenges. We address root causes and help dogs become confident and calm, providing solutions for behavioral problems with customized training in Denver.
Leash training
Obedience trainingProgram details
Professional dog obedience training to teach essential commands, improve manners, and build a solid foundation for behavior. Ideal for dogs of all ages, ensuring they are well-behaved at home and in public. Serving Denver and nearby areas.
Puppy trainingProgram details
Trusted puppy training in Denver to build confidence and teach basic commands. We guide your puppy through early learning stages for better behavior, social skills, and obedience. Perfect for new dog owners in the Denver area.
Socialization
Behavior support
Aggression trainingProgram details
Specialized training to address aggression toward people or other dogs. We identify root causes and use proven techniques to build trust, improve behavior, and ensure safety. Tailored for lasting results and a stronger bond with your dog.
Specialized aggressive dog behavior training to reduce reactivity and manage aggression. Our expert trainers help your dog overcome triggers and develop safer responses. Ideal for dogs showing aggression toward people or other dogs.
Fear and confidence
Reactivity trainingProgram details
Fast, effective reactive dog training in Denver for dogs that bark, lunge, growl, or struggle around other dogs and people. Practical training that gives you and your dog confidence and peace of mind.
Resource guarding
Separation anxiety
How training happens
Board and train
Group classes
Owner coachingCustomer-reported
Private trainingProgram details
One-on-one private dog training tailored to meet your dog's unique needs. Focus on obedience, behavioral issues, or aggression with customized sessions designed for faster results. Serving Denver with personalized, professional dog training solutions.
Dog age
Puppies
Support between sessions
Homework and practiceCustomer-reported
Personalized training plans
Assistance and working dogs
Protection trainingProgram details
Protection dog training in Denver focused on control, obedience, confidence, and reliable behavior. Training is tailored to the individual dog, owner, and their goals.
Dog size
Large dogsCustomer-reported
Your dog’s background
Rescue dogsProgram details
Dog training in Denver for rescue dogs adjusting to a new home or dealing with fear, anxiety, reactivity, or behavioral issues. We help build the bond between you and your dog.
Consultations
Free consultation
Other listed services
View 29 additional details
Dog trainingProgram details
Professional dog training to improve obedience, resolve behavioral issues, and reduce aggression. Tailored training programs for dogs of all ages and breeds, designed to achieve quick, lasting results. Serving Denver and nearby areas.
Aggressive Behaviors
Basic Commands
Behavioral Evaluations
Behavioral Program
Canine Rehabilitation
Court-ordered dog trainingProgram details
Court-ordered dog behavior training for legal compliance. Our training includes professional, detailed reports to meet court requirements. Available for Denver pet owners needing a thorough rebuilding of their dog's behavior.
Dog Behavior Assessments
Dog Bites
Dog Evaluations
Dog Park
Dog Starts
Dog Trainers Schedule
Dog behavioristProgram details
Dog behaviorist specializing in solving behavioral issues like anxiety, fear, aggression, and reactivity. We provide tailored, humane behavior solutions to help dogs thrive in any environment. Serving Denver and surrounding areas.
Dog's Barks
Dogs Treats
Family Dogs
Guard Dogs
Obstacle Courses
Off-leash dog trainingProgram details
Expert off-leash dog training to ensure your dog listens reliably, even without a leash. We focus on building recall, focus, and responsiveness, providing the freedom to explore while staying under control. Serving Denver and nearby areas.
Shelter Dog
Dog Temperament Assessment
Dog Temperament Test
Working Dog Training
Dog Anxiety TrainingProgram details
Trusted dog training for anxious. We work on building confidence, creating structure, and transforming your dog's behavior.
Seperation Anxiety Dog TrainingProgram details
Separation anxiety dog training in Denver for dogs that struggle when left alone. We’ll build a practical training plan to help your dog become confident and independent.
Destructive Dog TrainingProgram details
Dog training for destructive behaviors like chewing and damaging the home. We’ll help your dog building better habits, boundaries, and structure.
Dog Expert WitnessProgram details
Expert witness services for dog-related legal matters. Professional insight into canine behavior, temperament, aggression risk, and other issues in legal cases.
Dog Behavior Consulting for Legal MattersProgram details
Professional dog behavior consulting for legal matters. Experienced insight into canine behavior, aggression risk, evaluations, and other factors relevant to legal cases.
Confirm current programs and availability directly.
Questions & answers
From Google
What people have asked about this business.
Do you offer protection dog training?
Hi there! Yes, we offer Colorado's most trusted Protection Dog Training. We'll provide an assessment to ensure your dog is right for the role. Then we'll embark on a training journey that transforms your companion into a protection dog, and you into a strong handler. Please get in touch if you have more questions!
Community answer · Ancillary K9 Dog Training · 2025-12-21
Are there certain breeds that your dog training works best with?
Hi there! Though we have extensive knowledge and experience with Schutzhund and working breeds, our training is designed to work for any breed of dog. All breeds of dogs can have behavioral and aggression issues, and our training is equipped to tackle them all. If you have more questions, please get in touch!
Community answer · Ancillary K9 Dog Training · 2025-09-21
I'm struggling with a dog with serious behavior issues. Training in the past hasnt worked. Do you have any guarantees for your training?
Hi there! We specialize in hard to train or "problem dogs." Training is possible, even if other programs haven’t worked in the past. We are experts in dog behavior & obedience, and we guarantee fast, drastic changes in your dog. All of our programs come with Our Lifetime Support Guarantee, which is our promise to stand by you and your dog until your goals are achieved, as well as offering re-training if necessary.
Community answer · Ancillary K9 Dog Training · 2025-09-21
Do you offer puppy training? I have a puppy that's already starting to show some aggression and is proving hard to train.
Yes, we offer trusted puppy training. We correct your puppy's behavior fast, ensuring they have the best start at life. Correcting their behavior when they're young is the best way to see them grow to be a well-adjusted and happy adult dog. We'd love to help you tackle their behavior issues. Get in touch to get started!
Community answer · Ancillary K9 Dog Training · 2025-09-21
Private dog training offers tailored attention for specific behaviors and learning styles. It allows for flexible scheduling and results in faster progress. Our sessions are ideal for addressing unique issues, reducing distractions, ensuring a safe environment, and meeting individual goals. Owners receive immediate feedback and benefit from a private, relaxed setting, making it a preferred choice over group or board and train programs.
Community answer · Ancillary K9 Dog Training · 2023-09-21
In our training approach, we draw from the same methodologies used by law enforcement, military dog handlers, top sport dog trainers, and world-class competitors. Our methods are dynamic and are tailored to fit each unique situation. The tools and strategies we use hinge on the specific behaviors you want to address, your dog's individual temperament, and your proficiency and comfort as a handler. Our goal is effective, holistic training.
Community answer · Ancillary K9 Dog Training · 2023-09-21
Do you handle training for court-ordered behavioral assessments?
Yes, we are well-equipped to handle court-ordered dog training and behavioral assessments. We understand the seriousness and sensitivity of these cases. Our team is able to provide comprehensive evaluations and design tailored training programs to address specific behavioral concerns. We're here to assist and ensure that both you and your dog navigate this process effectively. Please reach out to us to discuss your needs and learn more about how we can help.
Community answer · Ancillary K9 Dog Training · 2023-09-21
Yes, we have extensive experienced in addressing canine aggression. Whether it's biting, growling, or other aggressive behaviors, we employ evidence-based techniques to manage and reduce these behaviors. We understand that aggression can stem from various underlying causes, and our approach is both compassionate and tailored to each dog's individual needs. Our goal is to ensure safety and foster healthy dog-owner relationships.
Community answer · Ancillary K9 Dog Training · 2023-09-21
Yes, we absolutely offer puppy training! Starting early is key to a well-behaved adult dog. We recommend starting training for puppies once they reach 16 weeks of age and have been fully vaccinated against parvovirus. This ensures their safety while they embark on their training journey. Our puppy programs are tailored to the unique needs of young dogs, laying a strong foundation for future training. For a comprehensive overview, please visit our website.
Community answer · Ancillary K9 Dog Training · 2023-09-21
While our primary base is in the heart of Denver, our reputation has traveled well beyond city limits. In fact, we've had the privilege of working with passionate dog owners from as far as Vail and Aspen. This expansive reach underscores our commitment to excellence and the trust clients place in our services. Regardless of distance, we remain dedicated to providing premier dog training to help build stronger bonds between owners and their dogs.
Community answer · Ancillary K9 Dog Training · 2023-09-21
At the heart of our service, client success is paramount. We employ a diverse range of techniques and tools, ensuring each client benefits from the most effective and tailored training. Recognizing that questions and challenges arise, we provide unlimited phone, text, and email support between lessons, ensuring continuity in your dog's progress. Moreover, our commitment to you is unwavering, backed by our Lifetime Support Guarantee.
Community answer · Ancillary K9 Dog Training · 2023-09-21
We do not! We believe in providing holistic support throughout your training journey. Not only do we NOT charge for assistance between lessons, but we also prioritize open communication. To encourage this, we give all our clients direct access to their trainer's personal contact details. This ensures 24/7 availability for phone, text, and email support. We're committed to standing by you every step of the way.
Community answer · Ancillary K9 Dog Training · 2023-09-21
What is your policy if I am not happy with the training?
We operate on a mutual commitment principle. If you're fully engaged—attending sessions, asking questions, and completing homework—we'll match your dedication. Your input reflects the support you receive. While we're eager to help, progress requires joint effort. If you're fully committed, we'll stand by you and your dog until you achieve the goals you're aiming for.
Community answer · Ancillary K9 Dog Training · 2023-09-21
1/5Trainer is knowledgeable and the training itself was good. However, after the first session, scheduling became an issue and we were unable to find times that worked for both parties. As the owner notes in his response, we ultimately never completed the program. Despite receiving …Read full reviewClose full review
Trainer is knowledgeable and the training itself was good. However, after the first session, scheduling became an issue and we were unable to find times that worked for both parties. As the owner notes in his response, we ultimately never completed the program. Despite receiving only one session, I was not refunded.
I understand there was a no-refund policy, but I would encourage prospective customers to confirm scheduling compatibility before committing to a program that costs thousands of dollars. My issue was never the quality of the training—it was the customer experience when scheduling fell apart.
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Grace
5/5I truly enjoyed working with Dion, he made everything clear and worked really well with my dog Zeus. My dog is incredibly reactive, lunged at people and other dogs, was becoming incredibly aggressive with even me, I needed help and wasn't sure where to go. He's gone through obedi…Read full reviewClose full review
I truly enjoyed working with Dion, he made everything clear and worked really well with my dog Zeus. My dog is incredibly reactive, lunged at people and other dogs, was becoming incredibly aggressive with even me, I needed help and wasn't sure where to go. He's gone through obedience and he now walks close to me, listens when he is called, he is getting so much bettet around other dogs and people.This training has changed not only my life but my dogs life. I am incredibly grateful. I highly recommend anyone who is struggling to Dion!
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Laura Brougher
5/5At the time of this review I am halfway through my program with Dion/Ancillary K9. I have 2 Giant Schnauzers; a 3 year old female, Liesel, and a 7 month old male, Dieter. I had never done any formal obedience training with Liesel but had “gotten away with it” (really ??) because…Read full reviewClose full review
At the time of this review I am halfway through my program with Dion/Ancillary K9. I have 2 Giant Schnauzers; a 3 year old female, Liesel, and a 7 month old male, Dieter. I had never done any formal obedience training with Liesel but had “gotten away with it” (really ??) because she is fairly easygoing and manageable . . . “just” challenged with impulse control & focus, not always fun to walk, and pretty lousy at recall. However, when it became apparent early on that Dieter is on the “wild child” spectrum (strong-willed, smart, sassy, independent, mouthy, exhibiting some reactive behaviors, and OBSTINATE), I knew I was in for a rough ride if I didn’t quit messing around and seek professional help early on.
After a ton of research and meeting with Dion, I decided to move forward with Ancillary K9 and haven’t looked back. I can’t say enough how happy I am with my decision.
Why?
1. Dion knows his stuff, no question. You won’t find many like him as far as his background and experience in dog psychology and behavior, and his success stories (as attested to by many, many clients) speak for themselves.
His insights into dog (and people!) behavior and the ability to speak to the whys and wherefores of what’s going on offer a dimension that is critical to accomplishing the goals you have for your dog- and yourself.
2) Dion is an outstanding teacher. His ability to get his points across using spot-on analogies and humor help to put you at ease and create a comfortable learning environment. He takes the time to ask thoughtful questions and gather information that enables him to tailor his instructions and recommendations for YOUR specific situation/needs, and he actively solicits questions and input. His explanations about the use of various tools (such as prong and e-collars) address their purpose/role/function and how, when used correctly, they can really benefit the training process in ways that the average dog owner doesn’t realize or understand. If you're like me, this will go a long way in helping to establish a comfort level with incorporating these tools into your training program.
3) I find Dion’s communication style to be refreshingly “real” and enjoy working with him; he cuts to the chase and tells it like it is, but is also supportive and encouraging. He’s clear about the need for YOU to put the work in with your pup if you want to be successful. It’s obvious that he’s committed to helping clients (both canine and human) build confidence and achieve success. His willingness to provide lifetime support speaks volumes about that commitment and isn’t something you’re going to find with very many programs.
While Liesel, Dieter and I still have a lot of work to do, I’m excited about the progress we’re making and am particularly thankful to be learning the tools to help me survive Dieter’s adolescent phase.
Working with Dion is one of the best decisions I’ve made, without a doubt. It’s an investment for sure, but there’s no question in my mind that the pay out will be well worth it.
For any of you who are serious about getting the help you need to make life better for you and your pup, I would encourage you to make the time to meet and talk with Dion about your situation and how he can help. It will be well worth your while, and, speaking from my experience, could help improve your relationship with your dog(s)- and possibly save your sanity.
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Sean Nestorick
5/5Worth. Every. Penny. If you are on the fence, please just go to a consult. Your dog will thank you and you will thank you. You might even find you enjoy dog training as a hobby. Has the training been tough? Yes, but it was so worth it.
Our rescue puppy Jasper had a rough start t…Read full reviewClose full review
Worth. Every. Penny. If you are on the fence, please just go to a consult. Your dog will thank you and you will thank you. You might even find you enjoy dog training as a hobby. Has the training been tough? Yes, but it was so worth it.
Our rescue puppy Jasper had a rough start to life. He was surrendered twice because he was “such a horrible puppy” (actual quote from the previous owners). He had issues with other dogs and resource guarding. Walks were a nightmare. Taking him anywhere was a gamble. We often felt anxious about leaving the house and upon returning would find the floor peed on and my right AirPod chewed up. When we were home he was a loving, cuddly, amazing dog. We knew he wasn’t a bad dog, he just needed training.
So I set out to train him. Followed the typical “give your dog tons of treats even when they misbehave” approach and it didn’t work. So I sought out a professional. We were told by multiple trainers that Jasper was a hopeless case. He would bark, lunge and try to attack other dogs. One told us over the phone without even meeting with us in person that he should even be put down and then asked us when they could expect a first payment to start training. After venting to my mother in law one day about the problems she went on Google and found Ancillary K-9
So we gave them a call. From the get go Ancillary k-9 was different. We called and the lady on the phone laughed at the premise Jasper was hopeless and had us meet Dion. We went to the park and found Dions approach was very different: We tell the dog no. He had us work Jasper, gave us some homework and within one session, Jasper was walking without pulling. Within a week, we could leave the house without worry of him breaking out of the kennel. Dion also gives you an exact list of what to purchase and from where. He takes the guess work out of what equipment is needed and which kennel is the best.
Now that we are almost done with our program Jaspers world went from us keeping him at home to now the world is his oyster. He regularly goes places with us and we feel confident to tackle hard situations. Dion explains training in a way that teaches you to train your dog this gives you the fundamentals to be successful regardless of the situation. He answers all questions thoughtfully and very precisely. We leave every session with more hope and even more results. I can say also say his approach will change you into the leader your dog needs you to be. Your dog isn’t hopeless, your dog just hasn’t met Dion.
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Kimberly Bringas
5/5When I initially reached out for a consultation I was at my wits end with my 5 year old corgi aussie mix Cora. Her behavior was getting progressively worse and I didn't know how to deal with her. When I received a call from Vickie to schedule an appointment, I was brought to tear…Read full reviewClose full review
When I initially reached out for a consultation I was at my wits end with my 5 year old corgi aussie mix Cora. Her behavior was getting progressively worse and I didn't know how to deal with her. When I received a call from Vickie to schedule an appointment, I was brought to tears with how incredibly kind she was. She helped me feel at ease and I was a bit more hopeful after booking the consultation.
The first thing Dion did was confirm Cora wasn't aggressive, but reactive. This helped me understand her behavior and he explained how we could leverage his training techniques to reduce her overall fear levels. He was very upfront about his expectations and for Cora to truly be successful I needed to be all in on her training. I signed up right after the consultation.
While it was a very intense journey that required me changing a good amount of my own behaviors, I am incredibly grateful to have had Dion as my guide. One of the most powerful lessons I learned from him was to set realistic expectations for Cora. I had these ideas of how my dog "should" behave that weren't fair to her as it was putting her in unnecessarily stressful situations. While I did need to be on top of booking sessions and take time off from work to attend sessions during the work week, Dion's training program was worth the effort. I was initially nervous to use tools like a prong collar, but Dion was very good about explaining to me how to use the tool to communicate what I wanted from Cora. After each session I had homework and over the weeks I started to see drastic changes in Cora and myself.
Flash forward almost a year after training, Cora is a confident and well behaved dog. She no longer has issues staying in her crate and entirely ignores other dogs on walks, even when they bark at her. I'm better at reading her body language and advocating for her needs. I can take her to crowded parks, sit with her in a coffee shop or restaurant and take her with me on errands. Dion also provided helpful guidance of how to introduce Cora to other dogs. While she still gets nervous I notice she looks to me for reassurance and knows I will intervene when needed.
Overall, I highly recommend working with Dion as it not only reset my relationship with Cora, it also gave me a training foundation for any dog I have in the future.
Original customer experiences from the collected Google data. Ratings without comments follow written reviews.