Get a spray bottle and spray him/her in the face with water when you see them do it.. they'll get over it really quick..
It could be worse: The place we just moved into ......the previous owner had a dog. Well, my dog found the other dog's calling cards in the backyard and has been quite fond of rolling around in it. To make it worse, he usually does it first thing in the morning, when its nice and moist outside. Ill tell you guys right now, nothing beats waking up at 5 am for work, taking your dog out, and then having to wash another dog's **** off of him right before an hour long commute.
I have an actual solution. Put lots of meat tenderizer in the food when he eats it. It worked for my dog when he was a puppy.
My dog, Jake, used to do this all the time when he was a puppy but it was more cat poop than his own or other dog poop. I can't really remember how I got him out of doing that, but it is like someone else said, it is pretty common for that to happen with puppies. Once they get to a year, they quit doing that for the most part. The spray bottle idea suggested by Da-Glyde is a pretty good one.
One of my Ridgebacks will always seek out and eat other cat's poop. She will also roll all around in duck poop if you give her the opportunity. This is why, when I look at people who love their animals so much that they french kiss their pets basically, I sit back and think about how stupid they are cause their being french kissed by a poop eater with Lord knows what else living in that mouth. My understanding is a dog's mouth is a very unhealthy place to be. That's why you can never assume you will be okay if your bitten by a dog. Hey...at least my dogs never ate their own poop. Your dogs are sick, man. Don't they know their eating their own poopy stank? lol
The theory is that they eat their own, or other animals' poop, because it has certain bacteria in it that is necessary for digestion. The may need a change in diet if they are eating their own turds. He he.....turds.
I had always heard that dogs ate cat poop because catfood contains so much more protein than dog food... I could be totally wrong though.