What is the Hatchinator's central slot for?

Gold-bordered eggs cannot be loaded into any of the regular outer slots.

The default Hatchinator at the Outpost has three slots to incubate three eggs at the same time, but only the middle position accepts special or perfect golden eggs.

Placing a golden egg into that middle space starts an incubation period of 5 hours. You do not need to keep the game open, because egg incubation timers continue counting down while logged out or offline.

Speeding up the five-hour countdown

Visiting friends can interact with the egg at your Homeland to shorten the wait. Each Caress interaction removes 10 minutes from the remaining incubation time. The machine tracks this with an on-screen 20-use counter, giving you an allowance of 20 caresses. Petting an egg also reduces its incubation timer by 10 minutes.

Other bonuses reduce the wait further. The monthly pass cuts hatch time by two hours. Hatching can also be sped up with real money, while active egg acceleration events shorten incubation or hatch eggs instantly.