ABSTRACT
The existence of an immunoglobulin G (IgG)-like molecule in chickens was reported by Klemperer (1) over 100 years ago. This molecule was determined to be the major serum immunoglobulin in hens and was named IgY due to its deposition
in the egg yolk to provide passive protection for the developing chick. The immune system of the chicken, and in particular IgY, has since been studied extensively, revealing the many important characteristics and applications of IgY.
