A method of isolating a newborn calf from the calf's mother. A rigid pen, including an outer frame defining an open floor attached to a motorized vehicle. The vehicle is operated to raise the pen off the ground and deliver the raised pen to an area at which the calf and the mother cow are located. The vehicle then positions the raised pen over the calf. Finally, the pen is lowered such that the calf is inside of the pen and the mother cow is outside of the pen. In one embodiment, the frame defines an opening at a side adjacent the motorized vehicle, with the method further including the vehicle operator entering the pen via the opening. In one embodiment, the pen further includes a foldable inner cage attached to an interior of the frame.