A method apparatus and system for delivery of live or attenuated viral and bacterial vaccines to fowl are described. The system comprises a) an apparatus for applying an effective amount of the vaccination agent to a population of fowl comprising a refrigerated vessel (100) configured to contain a pressurized aqueous vaccination composition a delivery outlet (18) configured to provide fluid communication between the vessel and a valve and a nozzle (26) in fluid communication with the valve (24) such that when the valve is actuated the composition is applied to the fowl b) an application hood (400) defining an application space in which the nozzle is positioned c) a conveyor (410) configured to transport a population of 1 5 day old chickens on a defined path such that upon passing in proximity to an actuation detector (420) the valve is actuated and when the population is transported along the path beyond the actuation detector the valve is closed.
