Poo from grass eating animals is good for your dog as they can digest the roughage better when it is second hand! But eating their own poo is a difficult one, my brother's border collie is a pest for it, she eats her own poo and my dogs if she gets the chance. We have tried everything to stop her but to no avail. Incidently she does eat tinned dog food, where as my dog has a natural diet and has never eaten her own poo.