The amino acid sequences of chicken MHC class I molecules belonging to the B4, B12, B15, and B19 haplotypes were obtained from GenBank (B4, GenBankID: CAK54654.1; B12, GenBankID: BAG69386.1; B15, GenBankID: BAG69413.1; and B19, Gen-BankID: BAG69441.1). BLASTP was performed to search for homologous proteins in the Protein Data Bank (PDB) using the BlOSUM62 Scoring Matrix optimized with a gap penalty of 11 and a gap extension penalty of 1. The MODELER [27] program was then executed in DS2.5 to construct the 3D structures of chicken MHC class I molecules for the four haplotypes. The quality of the 3D models was evaluated with a Ramachandran Plot using the PROCHECK [28] program and the Verify Protein (Profiles-3D) program [29] in DS2.5.