Our caring and compassionate veterinary care team!

Meet the Veterinarians & Team of Chatfield Veterinary Hospital in Littleton! We’re pleased to provide exceptional vet care for your pets!

Please call us at (303) 978-9750 to speak to one of our caring veterinary staff members!

Our Doctors

Tyler Renehan, DVM - Medical Director

Dr. Tyler Renehan received his D.V.M. degree from Colorado State University in Fort Collins, CO. He has worked at several small animal general practices since his undergrad years and completed several externships at small animal hospitals – most recently at PetAid Colorado, a non-profit veterinary hospital in Denver. As an “Air Force brat,” Tyler moved around the country numerous times as a child, but settled down in his parents’ hometown of Colorado Springs when he was 8 years old. Tyler and his wife Trish have a Labrador mix named Ellie, and enjoy spending their time hiking, fishing, and exploring the local breweries.

Amanda Naturman, DVM - Medical Director

Dr. Amanda Naturman is from Chicago but went to college and veterinary school in Florida. She graduated from the University of Florida’s vet school in 2015.  After veterinary school she completed a one year small animal internship at Colorado State University.  The past two years she has been working in small animal general practice in Gainesville, FL while her husband finished veterinary school there.  In her free time she loves to hike and explore the outdoors, which is what brings her back to Colorado.  She also loves cooking, running, traveling, and spending time with her husband, Dan, and cat Ripley. 

Marketa O'Neal, DVM

Dr. O’Neal was born and raised in the Czech Republic. She graduated from the University of Veterinary and Pharmaceutical Sciences Brno in 2015. She has completed several externships during her studies, including one in Purdue University College of Veterinary Medicine in Indiana. She spent some time after graduation traveling the World and volunteering as a veterinarian in non-profit organizations, such as Soi Dog Foundation in Thailand. After a small animal internship at Referral Veterinary Clinic VETINO Jaggy in Prague, she moved to California. She obtained her ECFVG certificate in 2018, and ever since then has been working as an Associate Veterinarian in a small animal general practice in Ventura, California. She and her husband Tim are avid nature lovers, which is why they moved to Colorado in 2021. She enjoys hiking, camping, mountain biking, reading, and spoiling her 2 cats named Odin and Ta Moko.

Madeline Hirshan, DVM

Dr. Maddy Hirshan graduated from Tufts University, Cummings School of Veterinary Medicine in Massachusetts in 2018. The following year she completed a small animal medicine and surgery internship at VCA Alameda East Veterinary Hospital in Denver. Dr. Hirshan then worked at other small animal practices before joining the team at Chatfield. Her areas of interest include internal medicine, emergency medicine, and surgery. She is originally from New York and relocated to Denver with her fiance, Ian. They now live in Littleton with their dog, Coriander, and two cats, Clove and Sage. In her free time, Dr. Hirshan enjoys cooking, baking, hiking, as well as exploring the growing Denver food scene.

Our Pet People

Jessica, Dog Trainer

Jessica joined the Chatfield team in August of 2009 after graduating from Colorado State University with a degree in Animal Science. She also has three associate degrees in Exotic Animal Training. Jessica is a certified trainer and offers puppy socialization and basic training classes here at the clinic and also offers private training classes where she can come to your home. When she is not at the clinic she spends her time with her beautiful family including two dogs and a cat!

Katelyn, CVT

Katelyn started at CVH as a receptionist but her love of animals lead her to the Bel-Rea Institute of Animal Technology. Luckily for us she chose to stay with Chatfield after graduation where she became one of our valued veterinary technicians. She has two dogs of her own, a Chihuahua named Bentley and a mixed breed named Pico. When she isn’t working, she enjoys spending time with her husband, her beautiful daughter and family four-wheeling in the mountains.

Hannah, CVT-Tech Supervisor

Hannah first came to Chatfield as an intern from Bel-Rea. After graduation we knew we couldn’t let her go! She is a true animal lover and loves spending time outdoors, especially paddle boarding and hiking with her sweet pup Bender.

Dara, Technician

Dara is originally from Georgia, and just recently moved to Colorado! She comes from an equine background, and even went to school for equine science. She also competed with her horse for over 20 years. She spends most of her free time hiking with her Great Dane Tempe.


Kiersten recently moved to Colorado after obtaining her Animal Science degree from University of California, Davis! She is taking some time to gain more experience in the field before applying to veterinary school. In her free time, she enjoys exploring Colorado with her rescue pup Ivy!


Kate is a huge dog lover and has always had a passion for working with animals. She is patient with them and makes sure they all have a fun experience. She currently works at CVH part-time while also going to school for criminal justice.

Sarah, CVT

As a certified Veterinary Technician, Sarah loves what she does. Her passion for working with animals has lasted over a decade and it shows no signs of slowing down anytime soon. When she’s not in the practice, Sarah is trying to keep up with her three incredible daughters, a supportive husband, two rescued mutts, Goose and Yogurt, and Raingil, the Beta fish.

Our People People

Dominique, Practice Manager

Dominique was raised in Massachusetts but found her way back to Colorado in 2011. She has spent the last 10 years working and experiencing different roles throughout the animal field, but joined CVH in 2016. She spends most of her free time with her son Milo, and fur babies Moose the chiweenie and Mooni the sphynx.

Theresa, Lead CSR

Theresa was born and raised in Colorado with a life-long love of animals.She joined the Chatfield team in March of 2019. Coming from a home that always had a cat or dog (or both), she now happily shares her home with her husband and son, two kitties, and a puppy. She’s had a lot of adventures and jobs in her life, but now she’s excited to go to work every day and help take care of animals!

Katherine, CSR

Katherine has lived all over Colorado but has spent most of her time in small mountain towns. She started working with animals a few years ago at a grooming salon and then a horse barn. She would like to continue working with animals but is still exploring her future in the animal care field. In her free time she likes to hike and camp with her dog Calypso, and take riding lessons. 

Kim, CSR

Kim was born in Birmingham, Alabama but moved around all over the states because her dad was in the Army. She even lived in Germany at one point but found herself in Colorado because of her husband’s job. She has over 10 years of experience in various customer service roles, and enjoys getting to connect with people. She has 2 dogs, Jaxon who is a Carolina dog, and the other named Janus who is a Chihuahua mix. She loves to spend her free time with her animals and husband. 

Marianne, CSR

Bio coming soon

Our Daycare People

Kennel Manager

Stacey has always been a huge animal lover and has three pets of her own, a Labradoodle named Porter, an Old English Bulldog named Stella Luna and a cat named Sprocket! She enjoys being outdoors riding her horse and spending time with her family!

Assistant Kennel Manager

Jen grew up in Maine and has been in Colorado for 20 years and has been working with animals for the last 15 of those 20. She especially loves dogs and enjoys being able to spend her days with them. She likes to spend her free time with her dog Summer.


Kevin has a total of 6 dogs at home! He originally was attending CSU for computer science, but realized it wasn’t for him! Working at Chatfield has been incredibly rewarding to Kevin, as he is a huge animal lover! In his free time, he enjoys skiing, hiking, video games, and of course spending time with his pets!


Brittany was born and raised in Colorado. She enjoys artsy activities, traveling to new places, and spending time with her boyfriend and their 2 dogs Loki and Jarvis!


Mikayla was born in Hawaii but spent some time living in Japan and Maryland as well. She enjoys playing video games, reading, and making treats for friends and family. She has spent all of her life around dogs and has attended schooling for game design and animation.


Anna grew up in Colorado and has had a love for animals ever since she was little. She hopes to one day become a veterinarian and also aspires to own her own business helping animals. With her dog Charlie by her side, she will always have a love for all animals!


Bio & Photo Coming Soon…