The ASPCA states that some puppy mills can have up to 1,000 dogs under one roof. Because of the high volume of animals, the mill runner will often resort to housing them in wire cages. This results in the animals having poor locomotion.[14] Keeping dogs in wire kennels can lead to injury and damage to the dogs' paws and legs. It's also fairly common for these kennels to be stacked on top of each other in columns.[12] The conditions in these mills are so unsanitary that the animals are often coated in their own urine and feces, causing mats in their fur. Due to unsanitary conditions, puppies from mills will often have internal parasites, affecting their health.[15] Puppy mills are often unheated and this increases the number of deaths due to cold among the dogs used for breeding.[14] Conversely, the mills can also be too hot in warmer weather leading to hyperthermia.[16]
Other common conditions in mills include malnutrition and untreated injuries.[16]
Due to the frequently poor breeding conditions in puppy mills [17], puppies bred there often suffer from health and/or social problems. Puppies raised in a cramped environment shared by many other dogs become poorly socialized to other dogs and to humans. Dogs are then transported over long distances in poor conditions, sometimes resulting in animal stress and death. As the surviving mill dogs grow older, they are more prone to developing respiratory ailments and pneumonia, as well as hereditary defects such as hip dysplasia.[10] In addition, mill dogs are more prone to having problems with their temperament due to lack of socialization, enrichment, and positive human contact. Puppies from mills are usually sold as purebred dogs in an attempt to attract the higher prices associated with purebreds. However, due to the indiscriminate breeding practices of puppy mills, the dog may not actually be a purebred puppy.[18] A high population of puppies from mills are inbred due to uncontrolled breeding.[19] The vast majority of puppy mill animals are sold to pet stores by "dealers" or "brokers". Some puppies are sold by dealers masquerading as authentic breeders.
Puppy mills in the US often start with hundreds of female dogs which serve their entire lives in the establishment. The females are bred until they can no longer conceive puppies, and are often euthanized after that.[20] The conditions in puppy mills are considered inhumane because all of the dogs are in a small, dirty area which is confined with disease and bacteria. Because of the poor living conditions, dogs are often sick and malnourished. Food is often found crawling with bugs and feces is almost everywhere. Health issues that are prevalent in puppy mills consist of giardia, mange, heartworm, respiratory infections, and much more.[21]
