This, and eating deer, cat or bunny poop, is definitely one of the grosser things our dogs will do. However, it is actually a really common thing AND quite normal.
Our dogs learn this behavior from their mother's during puppyhood. It's mom's job to keep their puppies safe from danger in the wild so they instinctively clean up their puppies messes.
By clean up I mean, eat their poop. Yes. Eat their poop. Puppies can't pee or poop on their own when they are first born. So good ol'Mom must stimulate the puppies bodies so that they can pee and poop. Once the puppies can pee and poop on their own their mother will still eat their poop to keep predators from finding the den.
So as gross as this is it's pretty natural. Most puppies grow out of it and fairly quickly. There are the few exceptions though and I think it's safe for me to assume that if you are reading this you are probably living with one of them.
I am sorry. Even though it's normal it is still really gross. So for the reason you are reading this.
How can we get our dog to stop doing this disgusting, though normal behavior? Here are a few ideas.