Hen eggs are nature’s perfect source for the everyday diet worldwide. Several components of hen eggs have biofunctional properties in humans beyond normal nutrition and have the potential for being used as active ingredients for nutraceutical and pharmaceutical products. Consequently, extensive studies have been conducted over the past decades to extract these products and to determine their biological functions. There are various biological functions of egg substances reported in the literature including anti-inflammatory, anti-hypertensive, anti-microbial, anti-oxidant, blood cholesterol/lipid-lowering, immune modulatory, anti-toxin/allergen, and skin/cartilage/bone strengthening. The new generation of hen nutrition formula and immune-modulating technology may be employed to develop fortified eggs with enhanced chemical compositions and biological features, such as omega-3 fatty acids and egg yolk IgY antibodies. Owing to numerous bioactive compounds present in eggs, they may be one of the best natural sources for the production of novel value-added nutraceutical preparations.