The invention relates to spray applicator devices and methods of use for vaccinating, or administering probiotics to, avian animals. Said automated spray applicator device comprises a housing, at least one rapidly actuatable automatic spray nozzle, a programmable spray module, for controlling the automatic spray nozzle(s), and optionally a source of pressurized air for supplying pressure to the fluid prior to its entry into the spray nozzles； wherein the programmable spray module is in electrical, pneumatic or hydraulic connection with the at least one automatic spray nozzle； wherein the automatic spray nozzle(s) is(are) in fluid communication with a fluid reservoir/tank； and wherein the automatic spray nozzle comprises an electrical, pneumatic or hydraulic actuator and a nozzle tip.
