Copied from a previous comment per the search engine.
I have had a dog or two over the years that was a feces eater (coprophagia)
The only thing I found that worked, was to follow them around with a pooper scooper when you think they are due for a bowel movement, scoop and discard immediately, out of sight out of mind. After awhile they stop turning around to look for it. In my experience, it doesn’t matter what you feed them. Sometimes puppies will out grow this nasty habit as they mature. It is what it is. You cannot let these dogs alone with their feces.
Has the vet ruled out medical issues?
http://www.petplace.com/article/dogs/behavior-training/behavior-problems/coprophagia-in-dogs
PS: Do not free feed. Feed at the same time, twice a day and you will be able to predict when the dog will have a bowel movement.
Or, feed once a day when you are able to take him out every 2 hours (after eating) for at least 3 times to offer bathroom breaks. A long walk/exercise will speed up the process of elimination. It works.
Always have fresh water available.
