Chicken genomics has benefited from the rapid technological advances in the genomics of model organisms and man. A number of resources and approaches are now well established, in the chicken, including genetic markers and maps (both genetic and physical), quantitative trait loci mapping, comparative mapping, expressed sequence tag and bacterial artificial chromosome resources, and physical mapping. In addition, the next phase of gene discovery, functional genomics, is underway. Progress in mapping quantitative trait loci for growth and fatness traits will be discussed, as an application of these new technologies and approaches in the study of avian physiology and genetics.