VTN and infection: Due to different environmental and physiological conditions over lifetime, we predict age-class variations in the relationships between innate immunity (hemagglutination by natural antibodies and hemolysis by complement proteins), pathogen infection and plasma carotenoids in nestling and adult griffon vultures, with nestlings diverting more carotenoids from the blood stream to innate immunity than fully-grown individuals due to their potentially higher exposure and vulnerability to pathogens during the ontogeny of the immune system.