My Dutch Shep had same thing. Never very solid stools. I tried lots of foods, probiotics, yogurt, cottage cheese, rice... yadayada, but when I put him on 1/2 Honest Kitchen dehydrated and 1/2 TOTW, voila, problem solved. He is 6.5 months and the last month on this food has been great consistently and he eats lots of other things too, bully sticks, potato chews, various training treats. I can't tell you why but that is my experience.
I got samples at the pet food place and it did not matter which one I used. He is on KEEN now.
Good Luck, it is worth a shot.
Dutch Shepherd - Ptygo (Tee-Go) de las Flores