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
5/5Dion is a fantastic trainer! He always made himself available and supported us through our dog training journey. My dog Ivy used to bark and lunge on leash, jump on people as they walked through the door, and constantly eat food off the ground during walks. It was stressful an…Read full reviewClose full review
Dion is a fantastic trainer! He always made himself available and supported us through our dog training journey. My dog Ivy used to bark and lunge on leash, jump on people as they walked through the door, and constantly eat food off the ground during walks. It was stressful and I didn't know how to manager her. After working with Dion, those issues are resolved and now Ivy is well-behaved and the stress around those bad behaviors is gone! If you listen to Dion and put in the work, you will have amazing results!!
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Carisa Cook
5/5Our only regret is not signing up sooner! Our dog, Mikko increased in showing signs of fear aggression behavior. He demonstrated signs of reactivity towards select people and dogs on walks but especially towards children. While he is still a work in progress, as owners we learned…Read full reviewClose full review
Our only regret is not signing up sooner! Our dog, Mikko increased in showing signs of fear aggression behavior. He demonstrated signs of reactivity towards select people and dogs on walks but especially towards children. While he is still a work in progress, as owners we learned to be in the driver’s seat to be better equipped to handle his behavior vs thinking all of it is on our dog to correct. Very wrong! We built confidence to lead, prepare for behavior and anxiety before it happens, and take the reins to more peace of mind in aiding our dog become the best version of himself. Mikko is now heeling (doesn’t pull ahead), doesn’t try to outsmart us when giving a command, and sees our leadership as authoritative guidance to be his best self. Thank you so much to Dion for the tools to be better handlers, patience with us in this process and for all of the great analogies to aid us in learning process to train a more obedient dog.
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Mark Henry
5/5With Dion’s guidance, my dog-reactive dog has improved dramatically within just a few weeks. For years, my adopted Frenchie has been extremely aggressive towards dogs, to the point of biting people who get between him and other dogs.
We still have serval sessions with Dion left-…Read full reviewClose full review
With Dion’s guidance, my dog-reactive dog has improved dramatically within just a few weeks. For years, my adopted Frenchie has been extremely aggressive towards dogs, to the point of biting people who get between him and other dogs.
We still have serval sessions with Dion left- at this rate, my dog will be as obedient as a service dog by the time we finish. For anyone who wants to not only get their dog under control, but also learn effective dog training techniques themselves, I’d highly recommend getting in touch with Dion.
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Marc Schulman
5/5I adopted a one year old boxer mix with no prior training from a local rescue in January. Before I started working with Dion, my pup would regularly pull on the leash, approach other dogs without permission, and would rarely if ever come when called. Within the first two sessions…Read full reviewClose full review
I adopted a one year old boxer mix with no prior training from a local rescue in January. Before I started working with Dion, my pup would regularly pull on the leash, approach other dogs without permission, and would rarely if ever come when called. Within the first two sessions, he was well behaved on our walks and I was even able to take him on a backpacking adventure in the Rockies! Our bond is stronger than ever and I couldn’t be happier with my decision to invest in a private trainer.
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C. Dub
5/5We adopted a large breed puppy and immediately knew we were going to need help with training a dog who eventually got bigger than us! Lol
We called Ancillary k9 and Dion helped us with pointers throughout the initial few months of puppy stages. Then when our boy turned 6 months,…Read full reviewClose full review
We adopted a large breed puppy and immediately knew we were going to need help with training a dog who eventually got bigger than us! Lol
We called Ancillary k9 and Dion helped us with pointers throughout the initial few months of puppy stages. Then when our boy turned 6 months, he started training with Dion. Our dog responded immediately and was easily trained. He loved "doing his tricks" and has been a gentle, loving, giant ham sandwich ever since. This giant cuddle bug is a BIG clumsy boy, but his temperament is sweet, loving, gentle and protective of humans and other animals. Our boy is sensitive, well behaved, and knows more human words than most adults I know!!! You can let an infant give him treats and play or pull on him without a second thought because he is so gentle... We attribute all of this to early consistant training with Dion. Thank you for teaching us humans how to speak to communicate with our dog properly!
As far as training goes, the sessions are easy and it's all about repetition and discipline for you and your dog. I was hesitant to use either of the training collars. But Dion put them both on ME before he put them on my dog and showed me how they're used and how they're annoying but absolutely humane. I was very grateful he was patient with me during training, and our dog absolutely loved him. This big, goofy, spoiled, lazzzzyyyy boy is so well behaved because he took his "manners" classes with Dion. Thank you Ancillary K9 and Dion 🤙🏽
Original customer experiences from the collected Google data. Ratings without comments follow written reviews.