An additive feeder assembly includes a supply reservoir having an outlet and an outlet tube having a first end in fluid communication with the outlet and a second end located vertically higher than the supply reservoir. An air stream transports a first granular material discharged from the supply reservoir and into the first end of the outlet tube to the second end of the outlet tube. A granular material distributor is in fluid communication with the second end of the outlet tube. The granular material distributor has a top end configured for attachment to a feed supply for a second granular material, a central portion located vertically below the top end and configured to mix the first granular material and the second granular material, and a bottom end configured for vertically discharging the mixed first granular material and second granular material.

An additive feeder assembly includes a supply reservoir having an outlet and an outlet tube having a first end in fluid communication with the outlet and a second end located vertically higher than the supply reservoir. An air stream transports a first granular material discharged from the supply reservoir and into the first end of the outlet tube to the second end of the outlet tube. A granular material distributor is in fluid communication with the second end of the outlet tube. The granular material distributor has a top end configured for attachment to a feed supply for a second granular material, a central portion located vertically below the top end and configured to mix the first granular material and the second granular material, and a bottom end configured for vertically discharging the mixed first granular material and second granular material.

According to one embodiment a solid component mixing apparatus is provided that includes a mixing device, a first dosing device for supplying sand and a second dosing device for supplying a solid additive that are communicated with the mixing device. The mixing device includes a vertical mixing chamber with a rectangular cross-section, the contour of the chamber being formed by four side walls, such that two side walls opposite one another are wider than the other two walls. The chamber includes a first inlet communicated with the first dosing device and a second inlet communicated with the second dosing device, the second inlet being at a lower height than the first inlet, and the second inlet being arranged in one of the wider side walls of the chamber. Associated mixing methods are also provided.

Provided is a method of producing pet food in which food granules of at least two colors are mixed together, including: a food granule producing process of producing food granules of at least two colors and a mixing process of mixing the food granules of at least two colors, in which the food granule producing process includes a powder raw ingredient mixing process of mixing together powder raw ingredients to obtain mixed powder, an extruding and granulating process of supplying the mixed powder to an extrusion granulator to continuously produce food granules, and a coloring process of performing coloring by adding an additive solution that contains a coloring component to the extrusion granulator, and the mixing process includes a process of sequentially putting the food granules of at least two colors into a tank to be layered and a process of discharging the food granules from the bottom of the tank to obtain a mixture of the food granules of at least two colors.