The disclosure relates to a spray applicator system for accurately and precisely dosing liquid formulations, including vaccines and probiotic formulations, to caged avian animals. In particular, the disclosure relates to spray applicators, having improved acceptance by the avian animals, relative to more disruptive prior spray applicators. The disclosed automated caged spray applicator system is designed to attach to and function with automated poultry feeding systems, routinely used in poultry house settings.