Strikingly, high levels of antigen-specific egg yolk IgY can be produced up to 2 years when the bird is continuously boosted every three months. Furthermore, collection of yolk antibody is non-invasive without affecting the immunized chickens. Finally, the NoV-specific IgY showed excellent reactivity at a wide range of temperature and pHs (this report), an indication of highly stable IgY, important for clinical use