Dogs eat poop. Dogs don't mind, but humans do.
Puppies may consume their own faeces because they're still learning what's food.
Bored or anxious dogs may eat their own faeces. Alone or bored dogs do this.
Dogs punished for defecating in the house may eat their own poo to cover the evidence.
Cleanliness, stimulation, and positive reward can stop your dog from eating its own poop.