 IgG and IgA antibody levels.\ 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. Blood, bile and cloacal swab samples were collected pre- and post-challenge and analyzed for anti-*Salmonella* antigen-specific IgG and IgA levels using ELISA. Results were reported as average optical density (OD) values. A--OMPs IgG; B--OMPs IgA; C--Flagellin IgA. Bars (+ SE) with no common superscript differ (P\<0.00). n = 0.](pone.0000000.g000){#pone.0000000.g000}  Results 