My all black German Shepherd, Patty, had chronic diarrhea from the time she was about 10 months old. I took her to the Vet at least 3 or 4 times a year for this condition. After blood work and a basic exam, all I got was "that's a Shepherd" I was very frustrated as my dog had NO energy, slept most of the time, would not play at the dog park for more than 5 minutes etc.I tried every kind of food-food with rice, all natural food, chicken and rice (people food) and she still kept having diarrhea.She was also very over-weight even though I cut back on her food.I thought it was her lack of energy. I did find a grain free food that helped as long as that was all she ate.At our last Vet visit, one of the Vet's in the practice tested my dog's thyroid.It turned out her thyroid was not functioning at all!!She has been on the thyroid medication for two months (and will be for life) and she can eat everything (not that I feed her everything)!!She is a different dog now; she plays at the dog park, can't wait to go for her walks and is much more vocal than she ever was.She also lost 12 pounds while eating more food during these past two month.I wanted to pass this on as it may be the problem for many Shepherd's out there and it is not being checked.
Thanks for sharing your stories.