Chicago-based Mercy for Animals, a pro-vegan group, released the video, saying it showed daily activities in a warehouse-size chicken coop, identified as Norco Ranch on Mountain Avenue, during August and September.
In several scenes, an employee is shown wringing the necks of sick hens, then tossing their carcasses in a heap.
Other secretly-recorded video shows hens with open wounds in cramped cages, hens laying blood-stained eggs because of "collapsed uteruses," and hens wedging themselves between their cages and the egg conveyor belt, where they often die, according to the narrator.
Injured hens, "crippled and unable to walk, were deprived of food or water," the narrator says.
Some of the injured poultry were simply thrown into a pile, "left to die under a heap of rotting bodies," the video states.
Moark officials dealt immediately with the issue, claiming it was the work of one employee, who has been suspended.