A product stacking system may include an open bag detection subsystem and a product stacking subsystem. The open bag detection subsystem may agitate bags to cause product to be displaced out of open bags and determine if a bag is open by comparing a weight of the bag after the agitation to a target threshold. The product stacking subsystem may include a robotic arm and a controller that moves the robotic arm between posts of a bin based on an orientation of the bin. A turntable rotates the bin and can operate as an additional axis of movement of the robot.