A minimum of 1 amp must be passed through the sheep's brain to reliably induce insensibility. The placement of the electrodes on the sheep's head is of significant importance.
The photo above illustrates proper placement. Note that it is a different placement than when electrically stunning hogs.
Like with hogs, head only stunning is reversible. Sheep which are stunned with a head only stunner must be bled within a maximum interval of 30 seconds to prevent them from regaining
consciousness. An interval of 10 to 17 seconds is recommended.
Following up the head stunning with cardiac stunning allows more time for shackling which may be of importance in small plants. When cardiac arrest stunning is employed, one electrode
must be placed on either the forehead or in the hollow behind the ears, and the other electrode is placed on either the back or side of the body. The head electrode should not be allowed to
slide back onto the neck.