It is written almost everuwhere that GSD is a breed should be raised on and fed raw meat. I don't know what makes people repeating one and the same mistake: feeding your young tender puppy some kibble, starting with some little problem, which develops into a big problem with digestion while your dog's young organism is still capable of struggling, then trying to cure it with raw chicken breast and probiotics, and after that simply learning that everything your carnivour needs is a variety of raw meet and bones. Wheat, rye, potatoes and other products are rich in starch, which is responsible for mucus growth in guts and subsequent diarrhea. Grains like oats and rice (well cooked) are good for your dog. Until 2 months puppies should be fed six times a day. From 2 till 4 months keep to the 5 times maintenance, 4 x maintenance in between 4 and 5 months and 4-3 x maintenance in between 5 and 6 months. If for some reason the puppy didn't eat his portion, take it away immediately till the next meal with the new portion in the appointed hour. But, the formation of the feces takes its time despite puppy's fast digestion. Say, if you feed him 5 times - ideally, he must ask to take him outside for the purpose two-three times, not more. He cannot digest that artificial stuff you feed him.