I have a wonderful Boxer who is 4 years old. Cookie has had this unusual habit since she was a puppy. Before she eats she roots in the dry food, then moves her head to the side and seems to push down, then she roots again. She gets a primeval look in her eyes. At first I thought she was mentally ill but she is a sweet, fun loving, highly intelligent dog. Have you ever heard of this strange but true behavior?
Such primitive antics might be abnormal for some dogs, but Cookie is a Boxer. Boxers are extraordinarily goofy and almost anything is normal for them. They are characters.
Cookie is a smart dog. Maybe she’s savoring the bouquet of her food before eating. She may also be having a good time entertaining you. She sounds healthy. You are fortunate to have her.