Do tamed oviraptors promote pooping?
This may have been added to the linked page after this question was asked, but the wiki page for the oviraptor linked to in the question does state that it increases feces production, the very beginning of the "Utility" section:
"nce tamed, setting the Oviraptor on wander will increase the production speed of eggs in nearby tamed creatures (including mammals), indicated by an egg icon above all affected animals. This effect will also increase the feces laying rate on all dinos nearby."
As far as I know, every time a female dino defecates there is a 2% chance to also drop an egg, so with that logic in mind, I suppose it is not out of the realm of possibility that it also increases the amount of defecation.