It's known as coprophagia and simply means poo-eating (!!). Training a 'leave it' command effectively, working diligently on reinforcing it, and being very vigilant on walks is the best way to address this. You can try doing things like feeding stuff that makes them less likely to eat their own feces but this really doesn't help if your dog eats others' feces.
I have two dogs that will go for cat poops in a second, but not dog poops, so they have a variety of tastes in this dept :lol:.
This is an excellent guide to how to teach this command and is bascially what Tara and Lisa at Dog Training Ireland use:
http://members.aol.com/ambrstar/kglic.htm
However Tara and Lisa start with NOT saying anything the first few times, just closing your hand and pulling it away (as if you are doing a curl with a weight in your hand, lifting your closed fist towards your chest) , saying nothing, til the dog hesitates, then praise and immediately give the treat in the other hand (NOT the hand with the treats you are saying 'leave it' about). About the 4th or 5th time, introduce the command.
Tara and Lisa also teach this using the phrase 'take it!' for the hand that has the OK treat. Training this way means you teach two commands at the same time.
You'd be surprised how quickly a dog will learn 'leave it' but note you MUST practice this daily for a while, even a few short stints a day (say 5-10 minutes a few times a day) to reinforce it, and once the dog really gets it, reinforce with practice regularly (a few times a week; this should be fun for you and the dog). The more your reinforce, the more effective and fixed the command becomes. Take treats on walks so that you can proffer a treat as a reward to further reinforce that good things happen when poo isn't eaten :lol:.
BTW what kind of lead are you using? A flexi or long lead is going to give the dog way too much freedom if you are having problems with feces eating as the dog will have swallowed it long before you even see it. Start walking on a four-foot lead and that should really help.
:yuk: