Dogs are known to eat their own sick also. I definitely think you should try what Jeanie suggested and look for something to feed him so that he stops. It can't be good for their health.
Have you spoken to a vet?
actually, Bliss, as horrid as it sounds, it won't hurt them. I had an old dog who took to eating goose poop :beurk: and my vet said it was just one of those things probably brought on by her age, and as gross as it was, it wouldn't hurt her.
A lot of animals do it (elephants are well known to actually stick their trunks up each others bums to get a mouthful of yummy poo). Its all to do with their digestive systems not being as efficient as it should be so a lot of digested and passed food is still full of nutrients, plus it has the added bonus of already been processed once so its easier to process the second time.
animals have been eating sh*t since there was sh*t to eat. theirs. ours. other animals. why stop them now? it doesn't hurt them. doesn't mean gonna take a fork to the front yard for a snack but then again I have thumbs and can open doritos. mmm. m nom nom