The H5N1 virus currently circulating is continuing to evolve, and it has already resulted in the extension of its host and geographical range. It is likely that H5N1 will become a global problem for the poultry industry. How many of the recent H5N1 changes observed have been induced by changing patterns in poultry raising? A change in attitude on the use of high-quality vaccines is a change that would drastically help in the control of the current epidemic in the poultry industry. This article provides an overview of the changing properties that have been observed during the current H5N1 outbreaks.