dogs: eating feces

Question
We have 3 Labrador retrievers and 2 Old English Sheepdogs with about an acre and a half fenced in grassy yard.  Major problem is two years, 6 months old male Lab, Jack and 8 month old male Webster both devour feces left by other dogs or themselves every chance they get.  Two year old female Jill also partakes to a lesser degree.  Our vet instructed us to keep the dogs lean and we feed a lot of vegetables (peas, green beans, carrots) mixed with Bil-Jac dry food.  Often, the vegetables (especially the peas and carrots) are excreted looking pretty much the same as when they were ingested.  This seems to tempt the Labs to eat the droppings but they will also eat more well-digested droppings too.  Needless to say we find this repulsive but cannot seem to stop them.  We have tried the food additives available but they do not work.  We clean up the yard as often as we can but it is inevitable that a couple of times a week the Labs will get to droppings and eat them before we have a chance to clean up.  Then their teeth and gums are coated and their breath intolerable.  Trying to correct with stern voice commands has little effect although occasionally we can distract them long enough to clean up.  It is getting to the point that Webster will follow the Old English around waiting for them to defecate and then gobble it right up!  Are there any food or vitamin supplements, indeed, ANY remedies for this situation?  In addition to the hygiene aspects, and the general level of disgust we feel, surely there are health implications for this "recycling" down the road.

Answer
You have already tried most of the usual remedies.  Since you are adding a lot of veggies, try canned pumpkin.  Have you tried the commercial products Forbid and Deter?  

I back your vet on keeping them lean.  Trying to feed them more so they stop it, would be more likely to shorten their life from over weight that the feces eating will.  

Some of the best info I have on it suggests it is due to diet.  I frequently run into it with my Lab puppies after I switch them to adult chow after 4 months.  A less rich diet when growing up can make a difference in borderline cases of joint problems.  You could try another dog food.  Not necessarily a more expensive one, but one made from a different base than the Bil-Jac.  I have heard nothing negative about it.  Most dogs will thrive on most commercial chows.  None of them are the right diet for all dogs.