Diseases remain a significant burden to poultry production and its future. Whilst it is widely recognised that vaccines have a major role in inducing protection, they can only be considered as part of the solution to this growing problem. Recent research efforts have focussed on developing effective preventative measures that reduce the risk of disease outbreaks in flocks. Optimising poultry flock health reviews the wealth of recent research on the mechanisms of transmission for infectious diseases, such as Avian Influenza (AI), and how our understanding of this transmission can be used to improve poultry flock health. This collection considers how improved surveillance, testing, diagnostics and nutritional strategies can be used as preventative measures, as well as how bird health can be optimised at the differing stages of production.