Coprophagia is simply to eat excrement. There are dogs that have this behavior and is a major reason for consultation with your veterinarian. Coprophagia has many variations: the dog can only eat their droppings, droppings can eat only dog ??or any kind of excrement is of the kind it is. We must look to recount to the vet.
It is often a medical cause, but in those cases coprophagy is a symptom in a wide constellation of problems. However, only a veterinarian can determine if a disease or disorder of behavior.
In those cases the reasons are several. There are so submissive dogs who eat feces the dominant dog of the group, as a simple expression of submission. In other cases the dog simply noted that its joint owner the dog excrement and its interpretation leads him to do the same, but the only way he can do that is eating.
In some cases the problem of interpreting the behavior of a female with young. In such cases the female usually eats the stool of puppies and it does for several reasons. First to keep the nest clean or place where the whole litter and secondly to avoid odors that may attract predators. There are puppies who confuse these behaviors and remain the same throughout adulthood.
The important thing is to look as if it is a medical reason must be, if a diet adjustment must be made or if a change of behavior must be corrected.