From Creatures Wikia
It can handle Norn, Ettin & Grendel Eggs. It works by teleporting any eggs it finds to the Eggonicer Cryovat and freezing them. By doing this it keeps all the eggs in the world frozen and in one place.
It then checks each of the Norn, Ettin & Grendel populations against user set minimum population values. Then thawing & teleporting an egg one at a time to their corresponding Eggceptor ready to hatch when needed to keep Creature population numbers as set.