Dr. Flahaven, DVM - vet in palatine

Dr. Mark Flahaven


Dr. Mark Flahaven has worked at Deer Grove Animal Hospital since December 2013.  He purchased the clinic in October 2015.  In the seven years prior, he worked for a corporate practice at various locations throughout the Chicagoland area.  He graduated from the University of Illinois, College of Veterinary Medicine in 2006.  He is a member of the American Veterinary Medical Association and the Chicago Veterinary Medical Association.  Dr. Flahaven is a Fear Free certified practitioner.  His love of animals developed at a young age while spending time at his grandparent’s farm in southern Illinois.  He spends most of his time with his wife Sarah and children, Charlotte, Violette, Margaret and William.  He also has several four-legged family members, two pugs named Kiki and Stinks, a basset hound named Lumpy and cats named Moonie, Dweebs, Lil Cat and Callie. 

vet office manager Sarah Flahaven

Sarah Flahaven

Office Manager

Sarah Flahaven grew up in and around Cincinnati, Ohio.  She grew up around with all kinds of animals: cats, dogs, chickens, goats and rabbits.  Living in a rural area, she showed goats at the 4-H fair and loved raising different kinds of animals.  She has a special place in her heart for beagles, as she had four pet beagles as a child.  After moving to Chicago, she graduated from Loyola University Chicago with a bachelor’s degree majoring in criminal justice.  She also obtained her paralegal certification and worked for a while as an investigator.  After meeting and marrying Dr. Flahaven, she decided to change her career path and dedicate her life to helping him and the pets at Deer Grove Animal Hospital.  It has been the most fulfilling career path thus far and spending time with the animals is the best reward.  She spends most of her free time with her children Charlotte, Margaret, Violette and William and her fur babies: Lumpy, Kiki, Stinks, Dweebs, Callie, Lil Cat and Moonie.  She is a Fear Free certified veterinary professional.

veterinarian receptionist Colleen Swanson

Colleen Swanson

Client Services Representative

Colleen Swanson became part of the team in the Summer of 2018. She has two cats; Gizmo and Gus who demand food and likes to sit on her puzzles while she is working on them (the puzzles, not the cats). Colleen has always had a love for animals at a young age, especially cats. After high school Colleen got a job at her local pet store where little did she know, her future employers were working in the same building.  In her free time, she enjoys going to concerts and Sudoku.  


Janeth Beltran

Client Services Representative

Janeth Beltran became part of the team in October of 2021. She is currently enrolled in nursing school but has always had a love for animals.  In her free time, she enjoys bird watching with her orange & white cat, Oreo.