I have a 15 week white purebred GSD and he has been really good for the most part. His name is Echo. I've been having trouble with him biting at me and the kids when he wants to play. I've tried the Yip method but it isn't working anymore. He's also started digging and chewing dead leaves and sticks. He had diarrhea for a bit but it passed and was meds. His stool goes from brown and normal to yellow smelly soft serve-runny all the time and his farts could kill anyone who dares to breathe. His food is Authority Large Breed Chicken and Rice. Can anyone help me with these problems or give some advice?