This article from Karin Brulliard in The Washington Post discusses some new theories on why dogs eat feces.
This is a question we are asked several times a year. Highlights from the article are:
This new paper from UC-Davis indicates that “…16 percent of pups consume other canines’ feces “frequently,” having been spotted doing it more than six times by their owners. The vast majority prefer their poop to be fresh, or no more than one to two days since deposit.”
The paper does not indicate why dogs eat feces. In fact, no evidence was found that connects poop-eating with age, diet, or compulsive behaviors such as tail-chasing.
The researcher behind the paper has theorized that dogs eat fresh poop to destroy parasite eggs found in the poop. When they consume the poop the acid in their stomach destroys the eggs.
Ma recommendation if you have a poop-eater is to pick up the poop and dispose of it immediately. It works. Always.