That secret is the existence of a sub-species of Changelings that they call Albino Changelings.
Albino changelings aren’t very common, mostly being one out of thousands of eggs hatched. They are thought to be a genetic defect within the species due to how deformed it is upon hatching. While normal grubs usually crawl toward their queen instinctively, Albino’s remain in their eggs, often being mistake for still-borns.
Appearance
As grubs: