Not as unusual as you may think. Usually caused by a dietary deficiency, animals will seek out that missing factor elsewhere. Dogs and coal or tar are a classic example, there is a mineral or trace element in there that your dog needs. Your vet can suggest a better alternative.
I know I'm the person who asked this question but I have completed a science experiment. I put coal on the ground and not far away from it was normal dog food. I then let the puppy in the room to see what object would it go to first. The first time it went to the coal, the second time it went to the dog food and the third time it went to the coal again. It does seem to have a stronger smell but then again I researched that puppies are likely to have a nibble at coal if it is around. If you are concered there are coal treats which can be bought from Pet's At Home or from America. They don't eat coal anymore when they turn older.
to give them calcium
no
Can dogs eat noodles
can dogs eat sauerkrauft
no leopards do not eat dogs
No, people do not eat dogs in Russia.
No, egyptians did not eat dogs.
NO, lol but dogs eat beans
No why would they eat dogs would you
Prarie dogs eat grass and weeds.
No, but rattlers eat prairie dogs.
It's not. Dogs can eat spinach.
Dogs will eat until they explode -they have been conditioned to eat while they still can.
they say when you eat hot dogs its really dogs but its not its just meat from a cow