It’s one of the most disgusting predilections a dog can develop: poop-eating. You might think that such a foul habit points to a nutritional deficiency or that it means Fido's not getting enough to eat, but actually, poop-eating (a.k.a. coprophagia) is a common pastime among dogs. It's quite normal, but still disgusting. In fact, female dogs with litters of pups have to lick their pup's rear end to stimulate pooping and the licking doesn't stop once the pup starts pooping.
Litter box morsels
Most dogs in all-dog households never show a proclivity for poop. In households where dogs and cats coexist, though, owners should take care to check Fido's breath before letting him say hello because dogs like cat poop the way kids like candy. Once a dog figures out that indoor sand-filled boxes contain tasty morsels of "used cat food," they frequent these sites in hopes of finding a "kitty roca surprise."
It's origin
How is it that a waste product could become a delightful dessert for some dogs? It all started thousands of years ago. Originally domestic dogs descended from hunters, but more recently the descendants have been scavengers. This tendency to scavenge can be seen in the present-day "wild" model of the domestic dog—the village dog. While dogs in the U.S. experience the luxury of a cozy home, free meals, and regular veterinary check-ups, three-quarters of the world's dogs are feral dogs, most of whom have chosen to live in villages near people. These motley mutts make their living by preying on stolen tidbits, human leftovers, and feces of all kinds. Those tame enough to hang out close to humans and indiscriminate enough to eat anything with nutritive value survive the best.
Among our coddled domestic dogs, many retain a strong desire to scavenge. They raid trashcans and left out lunch bags. A bias for dung depends on access to the morsels, the level of other interesting activities, and personal preference. Luckily for most owners, like humans who never develop a taste for escargot, many dogs never develop a taste for poop.
What can you do?
So what can you do if your dog likes to feast on feces? It doesn't hurt to try some of the over-the-counter products that supposedly make poop taste bad. Or to even lace poop with peppers regularly for several weeks—assuming they don't just learn the smell of chili pepper-laced poop. On the other hand, what could possibly taste worse than poop?
A more successful solution is to just deny access to the delicacy by cleaning it up ASAP. And don't waste time punishing Fido for exhibiting the horrible habit in front of you. He'll still snack on it behind your back. Rather, just call him to you before or as soon as you see him heading towards the stinky delicacy. Then reward him for coming when called and sticking with you instead of going after the poop.