Hierarchical classification analysis of 92 differential proteins in the egg albumen of unfertilized eggs produced by hens differing in hatchability (HH and LH) and embryonated eggs with healthy embryos (HE). Dendrogram (left) and graphs of the 6 clusters (right) showed the variation patterns of differential proteins for the HH, LH, and HE groups. HH, high hatchability group; LH, low hatchability group; and HE, healthy embryo group.