I was gonna say they have something in the middle of their body that would be their butt hole, but we just can't see it but the owl pellets sounds more intelligent and right, so let's go with that.
Reverse peristalsis.
If one of them sh*ts then it enters the others one stomach creating an endless circle of digesting sh*t
Maybe they're like owls and instead of peeing/pooping they throw up pellets like how owls throw-up owl pellets.
They vomit
Does it come out of one of their mouths or something?
