[Dreamer74]

I once had a vet tell me they are missing something in their diet, and there is probably a fair amount of unabsorbed nutrients left in the poo. That is not to say that what you are feeding them currently is bad it is just that right now their bodies are craving something else, more carbs, more protein, less carbs, etc.
So my recommendation is switch their food to something you normally do not feed, it will take about a week to see a change. We have done this with our Yorkie and with our Brittney Spaniels and it has always worked. And with our oldest Brittney who will be 11 this year there has only been 1 -2 times we have ever had to switch.
If that does not work I don't know.. I will say it has only worked to stop them from eating their own poo, the cat poop is still a delicacy.