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Meet Our Staff

Veterinarians Hospital Administrator
Veterinary Technicians /Front Office Staff


Dr. Scott E Heckerling
Co-owner and Medical Director


Dr. Scott Heckerling, Medical Director of Middlesex County Animal Hospital, is devoted to providing you pet with up to date, compassionate, and practical medical care.  He has eight years experience working in large referral veterinary hospitals where he has learned from board certified internal medicine, emergency, and surgical specialists.  Dr. Heckerling’s prior work experience has provide him with a unique understanding of all aspects of veterinary medicine.  He has an extensive knowledge of and practical experience in preventative medicine, emergency cases, and surgical veterinary care.  He feels at ease discussing the most appropriate vaccines for your new puppy, the best course of action for your vomiting cat, and the different surgical options for repair of the ligaments in your dog’s knee.

Dr. Heckerling grew up in Miami, Florida and attended the University of Florida undergraduate and veterinary colleges.  He graduated with high honors from the University of Florida College of Veterinary Medicine in 1998 and completed a one year intership at South Shore Animal Hospital in 1999.  For the past seven years Dr. Heckerling has gained invaluable on the job experience helping expand medical and surgical capabilities at the Animal Hospital of Nashua in Nashua, New Hampshire.  Dr. Heckerling has handled hundreds of emergency medical and surgical cases and has gained a reputation for exceptional customer service and patient care.  He loves to teach both his clients and staff and held the position of Director of Staff Medical Education.

Away from the office Dr. Heckerling relaxes at home with his girlfriend (and Middlesex County Animal Hospital technician), Kristy Williams, and their many pets (three dogs, a cat, three rats, a Sun Conure, a Beta fish, and a Corn snake).  He loves the mountains and gets away for skiing, hiking, and snowshoeing whenever possible.  He is an avid Boston Red Sox fan but unfortunately has remained a Miami Dolphin fan from his younger years.  His hobbies include dabbling in the stock market, weight lifting, fishing, and planning the next project around the house.


Dr. Evelyn Bailey
Doctor of Veterinary Medicine


Dr. Evelyn Bailey brings to Middlesex County Animal Hospital a wealth of knowledge, compassion, and experience having treated pets in this community for the past sixteen years.  Through the years, her enthusiasm for the veterinary profession has only grown stronger and she is always striving to learn the latest medical and surgical treatments for her patients.  Her strict approach to patient care and soft approach to client communication have earned her an excellent reputation.  The unique bond that she forms with both clients and their pets allows for open communication and puts owners at ease when making decisions regarding their pets. 

            Dr. Bailey has been involved in the veterinary profession and worked with animals for the past twenty seven years.  After numerous positions as a veterinary technician, Dr. Bailey graduated with undergraduate degrees in Animal Science and then in 1991 received a Doctorate of Veterinary Medicine from the Purdue School of Veterinary Medicine.  From graduation until April 2008, Dr. Bailey was an Associate Veterinarian at Silver Lake Veterinary Hospital in Tewksbury, MA.  Through the years, she has developed special interests in internal and alternative medicine, especially acupuncture.  Dr. Bailey is always focused on practical medicine for her patients and works closely with her clients to monitor their pet’s progress.

            Although Dr. Bailey has only been with Middlesex County Animal Hospital since April 2008, she has fit in perfectly and it feels like she has been here for many years.  Her clients are delighted with the facility and service. Dr. Bailey is extremely excited about the opportunities that Middlesex County Animal Hospital offers her clients and their pets.

From digital x-ray and ultrasound, to our well-equipped intensive care unit, Dr. Bailey feels that the quality of medicine and surgery she is able to provide her patients  is top notch.  Away from the office Dr. Bailey loves to garden, kayak, take walks on the beach, or just hang out with her fiancé Dan and their dogs Dudley and Dillon.


Dr. Kaitlin Crocker
Doctor of Veterinary Medicine


Dr. Kaitlin Crocker graduated from Tufts University School of Veterinary Medicine in 2010. As a new graduate Dr. Crocker brings to Middlesex County Animal Hospital a wealth of knowledge about the latest medical and surgical solutions available to our client’s pets. She spent clinical rotations at Tufts University working alongside board certified specialists with a focus on gaining surgical experience and practical medical care. Dr. Crocker has specific interests in internal medicine, dentistry, and ultrasound.

Having previously worked as a veterinary technician in a large veterinary hospital, Dr. Crocker has a unique common sense and practical approach to veterinary medicine. She has a very calm, clear thinking demeanor in emergency situations and an ability to make the most complex medical problems seem understandable. Dr. Crocker believes that pets are an important part of the family and is eager to help owners keep them healthy and happy.

Dr. Crocker grew up in Chelmsford, Massachusetts and is happy to still call that area home along with her fiancé, Keith, and cat, Gracie. She has always had a soft spot in her heart for Irish Setters. In her free time, Dr. Crocker enjoys training for her new found favorite sport, triathlons.



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Hospital Administrators

Mr. Joe Mercado, expert veterinary ultrasonographer,
hospital manager, and co-owner


Mr. Joe Mercado has devoted his life to serving the veterinary medical field and has 20 years experience as a veterinary technician and ultrasonographer.  Mr. Mercado began doing veterinary ultrasounds with Dr. Tom Rossi back in 1985 when very few veterinary offices had ultrasound capabilities.  The two would travel from Rhode Island to Portland, Maine in a day performing ultrasounds on sick dogs and cats.  Today Mr. Joe Mercado is one of the best ultrasonographers in his field, performs dozens of ultrasounds per week, and is highly respected amongst area veterinarians who refer their patients to him for ultrasounds.

With the opening of Middlesex County Animal Hospital, Mr. Joe Mercado has full filled his life long dream of owning a veterinary hospital.  Having grown up in Lowell, Massachusetts as one of eight children, Mr. Mercado has strong ties in the Billerica community and is excited about giving back to its residents and their pets.  Mr. Mercado has two decades of veterinary technical experience and has spent the past eight years at a large 24 hour referral hospital in Nashua, New Hampshire as the head veterinary technician, ultrasonographer, and hospital diagnotics manager.

Away from the office Mr. Joe Mercado spends time with his wife Melissa and their dog Echo.  Mr. Mercado is an avid weight lifter, runner, and occasionally picks up a pair of boxing gloves to relive his younger Golden Glove days.  He is an avid New England Patriots fan and has not missed a home game in three years.

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Veterinary Technicians/Front Office Staff

Miss Kristy Williams, CVT and puppy trainer


 Miss Kristy Williams is an animal lover through and through.  She has spent the last 12 years in veterinary medicine and recently became a certified veterinary technician after completing a two year medical program.  Miss Williams spent three years as an animal technician for the Army and more recently worked as an outpatient nurse and anesthesia technician for the Animal Hospital of Nashua.  Before coming to Middlesex County Animal Hospital, Miss Williams worked in the ICU, emergency, ophthalmology, and surgery departments at Massachusetts Veterinary Referral Hospital. 

Miss Kristy Williams began training puppies for the Air Force in 1996 and has been helping new puppies owners ever since.  She trained under Dr. Michelle Posage, a veterinary behaviorist, while running weekly puppy classes at the Animal Hospital of Nashua.  Miss Williams uses a positive reinforcement style of training proven successful by many prominent behaviorists.  She is an extremely knowledgeable, patient trainer and her years of experience will translate into success for you and your pet.  Her two sweet, obedient German Shepherds, Cassie and Ty, are proof that her methods work.

Miss Darci Corrigan, CVT


 Miss Darci Corrigan quickly worked her way up through the ranks at her prior employer and comes to Middlesex County Animal Hospital with a wealth of knowledge. Beginning as a kennel technician three years ago at the Animal Hospital of Nashua, Miss Corrigan demonstrated a fierce work ethic, love for the patients, and a thirst for learning everything about veterinary medicine. In just three years she was promoted to veterinary technician status and became the heart and soul of the hospital’s diagnostic team. Her primary interests lie in the areas of radiography and ultrasound but she always welcomes the opportunity to broaden her veterinary knowledge. Originally from Nashua, NH Miss Corrigan recently moved to Billerica. Outside of the office she loves to hike, go to the gym, and visit family in different areas of New England.

Melissa Heroux
Veterinary Technician, CVT, BS, MS


Melissa has an educational background in psychology and criminal justice but decided on a dramatic career change four years ago when she became a veterinary technician.  During the past five years, Melissa has learned a great deal about animals and the veterinary profession.  Fairly new to Middlesex County Animal Hospital, Melissa fits in perfectly and continues to learn new things everyday.  Melissa has an unbelievable attention to detail, an excellent rapport with clients and their pets, and ever expanding veterinary knowledge which has already made her an invaluable part of our team.  This year she passed her national exam to become a Certified Veterinary Technician.  Outside of the office Melissa enjoys coaching basketball, playing golf and flag football, or just hanging out with her two dogs, Boomer Gavin and Tessy Jean.


Nicole Overby
Veterinary Technician, CVT

Nicole came to Middlesex County Animal Hospital by way of Nebraska where in junior high she found her passion for helping animals through the Explorers Club.  Nicole graduated from Vatterott College in November 2006 with an Associates Degree in Applied Science of Veterinary Technology.  After becoming a Certified Veterinary Technician and working for one year in Nebraska, Nicole moved to Billerica to be closer to friends and family.  While at Middlesex County Animal Hospital, Nicole has demonstrated a great thirst for veterinary knowledge, compassion for patients, and a unique ability to bond with clients and their pets.  She continues to learn everyday both in the hospital and through online training courses.  Outside of the hospital, Nicole likes to read, spend time with her cousins, and enjoy the New England scenery.



Beth Brown
Customer Service Represntative

Beth has worked in customer service for the past thirty years; and over the past two years has become an extremely valuable part of Middlesex County Animal Hospital’s front office staff.  The combination of helping people and interacting with their pets suits Beth well as she has loved animals as far back as she can remember.  Beth has shown an incredible drive to learn as much about veterinary medicine as quickly as possible and has brought an outsiders perspective to the business.  She is a great client and patient advocate.  Beth is a lifelong Billerica resident and has two sons, Michael and Thomas; a dog, “Miss Jenny”; and three birds, “Sunny”, a Sun Conure, “Henry”, a rescued Cockatiel, and “Tweety”, a 12 year old Parakeet.  In her spare time, Beth enjoys cheering for the Red Sox and Patriots, reading, walking, and spending time with friends and family.




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