Dogs who eat poop usually have a nutrient defficency of some sort. It usually comes from a insufficient source of meat protein. Check the labeling on your dog food and see how much meat is actually in the food. I think you will be surprised to see it is mostly a grain based product.

My suggestion is to switch to a different food (such as Innova, Wellness, Eagle) which is made up of more meat than grain. See if you see a difference! You should also notice an improvement on your dogs coat too!!!