A formula delivery appliance generally includes a formula delivery head having features to mix, direct, and distribute formulation through nozzles to a desired location, such as the hair or scalp of a user. In this regard, the formula delivery head may include a plurality of nozzles configured to discharge the formulation at a desired flow rate. In some instances, the flow rate across the plurality of nozzles is controlled such that each nozzle has a flow rate within a specified percentage of the average flow rate across the plurality of nozzles.