Book 31, Question 74
What happens to the leftover yolk after a chick hatches?
Just before hatching, the chick pulls the remaining yolk into its belly.
The yolk is like a packed lunch that keeps the chick going while it is still weak. For the first day or two, the chick can live on it while it learns to peck and drink. It is a built-in snack that bridges the gap between egg and first meal.