Dog is eating poop (Dog is from puppy mill/ pet store)

Maybe your dog is bored and eating poop as a toy, another source of play. Especially dogs which have come from puppy mills or pet stores may see it as a toy because their former environment was so barren. 

The emotional stress from a restricted or small area or being left alone for long periods of time without the companionship of the caregiver sometimes can result in the eating of his own feces. 

Therefore, give your dog more daily exercise, interaction with his people and mental stimulation.

Your dog might be eating poop because of a rare illness called "coprophagia". 

There are some medical conditions that may cause coprophagia, such as Exocrine pancreatic insufficiency, Pancreatitis, Intestinal infections, and more. Get your dog checked out, just to be sure there is not a health problem that causes this unpleasant habit.

When a dog is fed low-quality or inappropriate dog food, it feels like it should eat more in order to satisfy its body's craving for nutrients.
 
Dog foods must contain some specific levels of fat, minerals, vitamins and proteins depending on the lifestage of the dog. There are many complete and balanced dog foods in the market:

1. Taste of the wild 

2. Rocco & Roxie Liver Treats

3. Diamond Naturals

A yard or kennel where stools pile up might prompt a dog to 'clean up' his poops. Be sure to clean this area every day, and preferably just after the dog eliminates.

There are some products to apply to the poops to discourage your dog from consuming them. You can find them in pet supply stores or from veterinarians. 

1. Forbid

2. Dis-Taste

3. NaturVet 

Some products are especially made to tackle this problem, e.g. check out this one.

Find the stool and pour hot sauce over it, e.g. Habanero sauce. This makes the poop uncomfortable to eat but won't cause any real damage. After a bite or maybe several, your dog will come to the conclusion that it's not worth it.