I suspect Olivia may be doing this (haven't actually caught her though) so I've been researching it. From what I've read, what they eat is a big contributor - for example, I was feeding strictly raw and then decided to try feeding kibble for one of her two daily meals. Since substituting kibble, her poo has gotten stinkier and bigger, and my understanding is that it's because it is not being digested as thoroughly as the raw diet was. And the undigested food is what gets their attention and they eat it.
Sooooo gross! So I'm going back to the raw diet, now I'll see if she has developed a habit that will continue or if she isn't interested in it anymore (hopefully the latter!)