Abstract
Controlling infectious disease is one of the major issues facing poultry breeders, particularly since the introduction of high-density rearing. The poultry industry relies primarily on animal husbandry and vaccination for disease control. Commercial poultry vary in disease incidence for most of the important avian viral pathogens; thus, selection for enhanced genetic resistance to disease offers another added layer of control. Furthermore, chickens with enhanced disease resistance would help poultry-breeding companies gain market share, maintain consumer confidence and improve animal welfare. Due to the high costs associated with pathogen challenge and the biological complexity of disease resistance, selection has been limited to very few viral diseases where the primary control methods of animal husbandry and vaccination may fail. With the advent of the chicken genome sequence and related genomic technologies, there is enormous potential to identify specific genes, mutations and pathways controlling disease resistance. The ensuing knowledge can be utilized to produce commercial poultry resistant to many more diseases using genetic markers and other indirect methods of selection. This chapter highlights the technologies that are making this advance in biological knowledge possible, specific diseases where cutting-edge technologies are being applied and future prospects.