This chapter reviews effects of supplemental full- or de-fatted microalgal biomass in diets for broiler chickens, laying hens, and other types of poultry on their production performance, meat and egg qualities, nutrient metabolism, and molecular responses. Different sources of microalgal biomass have shown excellent potential to replace a good amount of SBM and(or) corn without adverse effects. Meanwhile, microalgae are used to enrich chicken meat and eggs with n3-polyunsaturated fatty acids and bioactive phytochemicals for adding human health-promoting values to these animal products. The dual application of microalgae for producing biofuels and replacing conventional feed protein stands as propitious mediator to reshape the junction between intensifying animal agriculture and meeting the global needs for energy, food, and environmental sustainability.