Poop eating is actually fairly common and there is a name for it, coprophagia. Some experts think the first thing you should do is to check the food you are giving her because food that contains hard to digest proteins, will often leave some of the protein undigested, and this will seem appetizing to your dog. Some proteins are easier to digest than others. Another opinion is that the food is lacking in nutrients, again a food change might be advisable. If your satisfied with the food, some say that adding pineapple, or unseasoned meant tenderizer to the food helps, because it helps to digest the protein the first time around. This link has some other useful tips for stopping coprophagia, or more commonly known as poop eating.
Stopping Dogs From Eating Poop