Dogs eat poop for a reason - so that's what I'd explore before anything else. I would take this as a sign that you should change dog food immediately - what are you feeding...? With some dog food ingredients, they come out the other end still intact - undigested. This means that it STILL smells just like food - the dogs can smell that, making it still appealing to them - so, they eat it.
You want a food where everything in it gets as digested as possible - causing the poos to come out firm, formed, small, compact - and then dry up sorta fast....not appealing for dogs to eat, as there is no food in that kind of feces. Yuck, btw!
So, tell us what you're feeding the puppy and the other dog and maybe we can help there.
