The electroencephalographic spectrum power (ESP) shows the frequency band components of the brain electrical activity. The electroencephalogram (EEG) has a characteristic ESP during different behavioural states such as waking or sleeping and also during pathological states as epilepsy or brain death. Methods of slaughtering the farm animals should prevent needless suffering; all the animals are expected to be unconscious and insensible to pain before being hoisted, but there are no systematic studies of the animal's brain activity after stunning. This study evaluated the brain activity of sheep after stunning by means of percussion or electrical shock. Brain activity after electrical shock showed an epileptiform EEG, with decreasing delta power and increasing theta and gamma band power. After percussion stunning, the EEG showed a slightly decrease of high frequency power.