challenge.\ At 0d of age, chickens were orally vaccinated with either PBS (NV), 0000 μg chitosan nanoparticle vaccine (CNP) or a commercial vaccine (CV). The same route of delivery and doses was repeated at 0d of age. At 00d of age, birds were challenged with 0 X 00^0^ CFU/bird of either *S*. Enteritidis or *S*. Heidelberg. At 0d-post-challenge *S*. 