Impact of egg quality on hatchability of poultry hatching eggs: research progress and regulatory strategies

Egg hatchability is a key indicator of reproductive efficiency in poultry. Egg quality, which serves as the material basis for embryonic development, plays a pivotal role during incubation. Egg quality includes both external and internal components that influence embryonic growth and hatchability through the modulation of gas exchange, water balance, microbial barriers, and nutrient supply. External qualities, including eggshell thickness, strength, and pore structure, determine protective properties and permeability, whereas eggshell color and translucency reflect the structural integrity and mineralization status. Internal quality, including the yolk-to-albumen ratio, albumen freshness (Haugh unit, HU), and albumen physicochemical properties, affects the nutrient supply and stability of the internal environment of the egg. The effects of egg quality components are further modulated by management factors such as storage duration, storage temperature, and incubation conditions. This review summarizes the mechanisms linking egg quality to hatchability and outlines strategies for improving egg quality and hatchability.