Abstract
Hatching window and the gender of hatching eggs were investigated in relation to the yolk content and yolk ratio (yolk to egg ratio) of the eggs. To quantify the amount of yolk noninvasively, a regression model from absorbance spectra (600–900 nm) was developed using known yolk content. This model was then used to determine the yolk content subsequently the yolk to albumen ratio of the hatching eggs. This yolk information of hatching egg was then correlated with hatching time and the gender of the egg. The results showed a significant correlation between estimated yolk-albumen ratio and hatching time, but no significant correlations were obtained with the gender of the eggs.