Common Health and Behavior Problems in Puppy Mill Dogs

Adopting a former puppy mill dog can present a challenging adjustment period. Learn which behavioral and health problems you might expect.

Puppy mill dog health problems
Cute puppies on the internet often come from puppy mills. By Kristine Lacoste/Petful

You’ve decided to adopt a dog, but not just any dog.

A local rescue group picks up dogs when puppy mills are shut down, and you’ve decided to wait for one of those. The day comes and your dog is ready.

What can you expect?

There are many puppy mill dog health and behavior problems that you might encounter.

Behavior Problems

The first thing to realize is the environment of the puppies and dogs in puppy mills.

Most often they are in small cages that may not allow them to turn around, or they are in a pen with many other dogs. They may not have had any socialization with humans other than quick handling or during transport to another area for breeding.

Many times puppy mill dogs live their entire lives in small cages with wire floors; the wire allows waste to pass through for easier cleaning. You read that right; someone designed a containment method so the dog cannot even relieve itself somewhere else.

The dogs live in filth and waste with the typical cleaning method being a pass with a pressure washer (sometimes without care for the dogs; they have been known to lose an eye to careless washing).

Living in these cages prevents the dogs from experiencing different surfaces such as tile floors, carpet or even grass. In many cases they never see the sun because they live in dark warehouses or outbuildings.

As the new caregiver of a former puppy mill pet, you’ll need to be aware of these aspects in order to understand why your dog exhibits certain behaviors.

Behavior problems are expected and can appear in many forms in puppy mill dogs:

  • Fear
  • Trembling
  • Shyness
  • Aggression
  • Anxiety
  • Food aggression
  • Difficult to house break
  • Difficult to leash train
  • Lack of height or depth perception
  • Light sensitivity or avoidance
  • Surface sensitivity or avoidance
  • Hoarding (food or items)
  • Erratic sleeping pattern

When adopting or fostering a puppy mill dog, assume that your dog’s former environment was a worst-case scenario. Your new pet may exhibit all of the above signs, some of them or none at all.

Being prepared and patient is the key to helping your dog relax and become accustomed to a typical home.

Working with your veterinarian and a trainer (if possible) can help you find ways to work with your puppy mill dog and the issues you recognize.

Puppy Mill Dog Health Problems

Remember those wire-floored cages mentioned earlier?

The dogs can have their legs fall through those, their nails may become overgrown around the wires, and a host of other problems can be caused by the absence of mobility. The dogs are fed cheap food, assuming meal times aren’t missed. Their water is dirty and can be a breeding ground for mosquitoes and algae.

Waste can accumulate for days, creating the perfect environment for flies, infections and other gross things. Imagine the level of ammonia that must circulate within just one day.

Sadly, many puppy mill dogs will live their entire lives like this. They even breed in these conditions.

This doesn’t even scratch the surface of the other health issues your dog might have encountered. Given that there is no vet care or regular grooming, the list of afflictions is long.

Puppy mill dog health problems can include:

  • Epilepsy
  • Kidney and heart disease
  • Joint disorders such as hip dysplasia and luxating patellas
  • Endocrine disorders (diabetes, hypothyroidism, hyperthyroidism)
  • Blood disorders such as anemia or von Willebrand (blood doesn’t clot)
  • Deafness
  • Blindness
  • Eye problems such as cataracts, glaucoma, retinal atrophy
  • Shortened or missing limbs
  • Respiratory disorders
  • Matting
  • Mange
  • Mites
  • Scars
  • Periodontal and gum disease
  • Nail overgrowth or growth into the paw
  • Missing teeth
  • Heartworms
  • Fleas and ticks
  • Intestinal parasites

Despite this list of potential concerns, puppies from a puppy mill can appear as healthy and happy as a puppy from a responsible breeder — for a short time.

One story that sticks with me involves a family in the United Kingdom who had lost their pet. After about a year of grieving they finally decided they were ready for another dog. They found a puppy on the internet, met the “breeder” at a neutral place and took their new puppy home.

Within a few days the puppy was in severe pain and showing signs of illness. The puppy ended up having parvovirus and had to be euthanized shortly thereafter.

These conditions (and many more) can be present in puppies:

Again, working closely with your vet and a trainer can greatly help your former puppy mill dog recover, heal and adjust to life outside of the nightmare from which they were saved.

While this may all sound pretty horrific for the life of a dog, it happens every day. American breeders with licenses from the USDA rarely get inspected, and the care requirements are grossly inadequate.

Some of these dogs have AKC-registered parents and may come with their own prestigious-looking certificate, but a piece of paper cannot replace loving and responsible breeders.

If you are looking for a dog, please consider a rescue. While puppy mill rescues may offer additional challenges, consider the life-changing transformation of which you can take part. If you’re unsure whether a breeder is a puppy mill, please read and share this article as well as our puppy mill red flags article.

Remember: No demand = no profit for puppy mills. 

Until the government regulates and enforces these businesses online and locally, please join Petful in the fight to reduce their demand. Sign up for free updates on this issue as well as our twice-monthly email newsletter:

One last thing: Check out the photo and the caption below.

"Pets for sale" websites can appear harmless. Would you ever suspect that the owners of this website were running a puppy mill? They were charged in November 2012 with 723 counts of cruelty. Click to see their website as it once appeared.
“Pets for sale” websites can appear harmless. Would you ever suspect that the owners of this website were running a puppy mill? They were charged in November 2012 with 723 counts of cruelty and later pleaded guilty. Click here to see their website as it once appeared.

Additional Resources

Kristine Lacoste

View posts by Kristine Lacoste
Kristine Lacoste, editor in chief of Petful, has been researching dog and cat breeds for nearly a decade and has observed the animals up close at dog shows in both the United States and the United Kingdom. She is the author of the book One Unforgettable Journey, which was nominated for a Maxwell Award from the Dog Writers Association of America, and was host of a weekly pet news segment on the National K-9 Academy Radio Show. In addition, she was the New Orleans coordinator for Dogs on Deployment, a nonprofit that helps military members and their pets, for 3 years. Kristine has researched and written about pet behaviors and care for many years. She holds a bachelor’s degree in psychology, another bachelor’s degree in English and a Master of Business Administration degree.

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  1. Clarissa Fallis
    February 19, 2013

    BOO PUPPY MILLS! Dont buy from a pet store, ADOPT!

    A couple examples of puppy mill dogs I have worked with:

    1. Border Collie purchased from a pet store has heart arrhythmia and has a pace maker.
    2. I pulled a Boxer from a kill shelter that was a puppy mill breeder. She has -ZERO- paw pads and her feet were so sore and bloody. She was also body condition score of a one and had 5-6 litters in 5 short years.
    3. Cavalier King Charles Spaniel that had no knee joints.
    4. Dachshound that died two weeks after adoption after purchased from pet store. Died of Parvo.
    Unfortunately, I know I will have more stories in the future. :[

  2. Jai Bee
    July 3, 2014

    Toy poodle is scared of bathroom had ear infections and kennel cough, and is terrified of his water and food bowl. Standard poodle came from horrible conditions he had scabs on his thighs and face foot pads raw in some areas, is scared of men will bark at them. He whines almost constantly also had ear infections and is scared of leash, noises, tv, cars, and lots of other things he paces and spins. They both follow me around scared of everyone and everything else.

  3. Joe
    January 2, 2015

    My neighbor adopted a 7 yr. old female puppy mill rescue, which was used for breeding. She sleeps all day and shows no emotion at all. She has her for one and one half years and has never barked. I started taking her for walks twice a day and have brought her to a dog park. She shows no excitement or emotion when she sees other dogs. Any suggestions?

  4. Brandy Danielle
    October 4, 2016

    There needs to be much more serious penalties and punishments involved for the subhumans who operate puppy mills. There needs to be stringent criteria perspective breeders have to meet and there needs to be surprise inspections, and breeders should be given only the one chance to get it right. You fail inspection, it becomes illegal for you to be an owner of any animal.
    I know this’ll never happen because hell, we can’t even keep our own species (ex: children or elderly) from being horrifically abused, what possibility is there for us to successfully regulate something like puppy mills?
    Let’s just say my confidence in the ability of my fellow man is not high. Not high st all.

    1. Melissa Smith
      October 5, 2016

      I’m not going to lie, when I finished reading your comment I hollered “hear, hear!”


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