my dearly departed "MAX" the rottweiler who passed away this March- used to go under my rabbit hutch and eat his poopies. The dog was not under-fed by any means. He would also eat the cracked corn I put out for my chickens. Luckily, however, he never messed with the other animals.
Now I have a 4 month old Samoyed puppy "Tonka"- who eats newspaper, toilet paper, envelopes etc.... and he is well fed also.
In a way, I wish I craved to snack on paper- less carbs.....ha ha ha