My adorable little guy, Rocco

, for the first time this evening has eaten his own poop twice. I took him out like I usually do, always stay with him, noticed him to be chewing on something. At first I didn't find this too unusual, he eats grass occassionally. But then I notice it had to be more than grass turning out to be dried stool. (We clean up daily but must have missed some.) I told him to stop he took off towards the house I cleaned up left over stool turned to see he had a large piece hanging from his mouth chewing it - I told him to drop it , not wanting to grab it. Once in house cleaned his face brushed teeth(which he is not a fan of yet). So disgusting.

Why?