When I adopted Katie ten years ago, she had a raging bad habit of eating dog poop. Even on walks, she would dive for a pile from an unknown canine source. It was disgusting. She is the reason why we continue to muzzle our greyhounds. I was not going to have Katie wear a muzzle and not Travis. Then I got married and suddenly there were six greyhounds in the yard.... muzzling seemed like a good idea with so many. I know it seems so strange to non-greyhound people, but it is so nice not to worry about thin skin needing stitches when they are wrestling or get into a squabble.
Over the years, Katie's desire for poo diminished completely. For years, she was clean and sober.... until NOW! Like a ninety year old deciding to start smoking again... some bad habits die hard.
I do not believe most poop eating has anything to do with poor nutrition so no need to suggest miracle supplements. Katie is always HUNGRY. At the racetrack she was probably bored and hungry in the turnout one day. Gave poop a try and liked it. Once they start, it is a hard habit to break.