We are interested in using retroviral vectors to trace cell lineage and to introduce exogenous genes in chicken skin explant cultures. Here the LZ10 virus carrying the gene encoding beta-galactosidase was introduced to the skin explants by two different means: a) the virus was added to the media or b) the virus was microinjected into regions of the developing feather buds. Infection by microinjection led to localized expression of beta-galactosidase in the developing feather bud, while, surprisingly, infection by adding the virus to the culture media led to localized band of beta-galactosidase expression in the middle of the feather filament. The significance of this finding in skin morphogenesis and as a tool for experimental embryology is discussed.