>>96075202
The Hive don't have normal biological needs. They can eat but they don't need to because they essentially sustain themselves on the "killing" they do when they kill something. It's even explained when Oryx lays out the tribute system to regulate tributes so no one individual burns out accelerating the hunger of their worm beyond what they can manage (which is essentially the point Oryx and his sisters were at) so they can use some of it for themselves, some for their worm and then they have to pass the rest up the chain.

Before that, the Worm Gods were just stuck in the depths of Fundament and were slowly starving until the Witness' plan leads the siblings to them so they can take the Larvae