My 2yr old weim female also did this? We got her from a rescue centre,she has had a litter of pups while at the centre.I have now been told that this is a maternal thing? cleaning the pups genitals and bottoms.In doing this she is consuming faeces,i can only guess that this is learnt behavior.There are products you can buy from pet stores to help stop this it worked for my weim.
My bitch of 18 months still does sometimes, i have been given lots of reasons and solutions over this last year. One suggested they copy their mother who cleans up after her babies, another said its when they are missing vitamins??? I'm not sure if any of the reasons i have been give have any truth. As for solutions give them pineapple chunks, or banana, as they are not supposed to like it in their poo???? again sometimes it works sometimes it doesn't. Mine after 18 months sometimes still has ago ... i think she is just permenantly on the look out for any food as she is a total dustbin!
Inject a small amount of Tabasco or franks red hot into his feces and he will stop! It is quite simply just a very bad bad habit and can cause him to get seriously ill! Remedy this situation ASAP!!!! If the injections do not work seek professional help immediately. This is one habit you want to break as early as possible. A kitchen baster or old medicine syringe can be used to inject the feces. Also remove any feces from your yard immediately after he poops, and you may want to think about changing or adding to his diet because this can also be a sign he is not getting what he needs from his food, but more likely, he's just being a dirty boy!