A preliminary study was carried out to determine the minimum current required for head-only electrical stunning of force-fed ducks. Forty-five force-fed ducks were implanted with electrocorticogram (ECoG) recording electrodes, and the changes occurring in the ECoG frequencies were quantitatively evaluated with Fast Fourier Transformations (FFT) to determine the effectiveness of a range of electrical stunning currents. A 50 Hz alternating current (AC) was used to apply a constant current of 100 (n = 4), 200 (n = 12), 300 (n = 13), 400 (n = 9) or 600 mA (n = 7) for 4 seconds via electrical tongs (spiked electrodes) placed firmly on the ears. The feathers on the head were wetted using saline water to improve the current flow through the skull. The birds were manually bled out within 15 seconds from the end of the stun by severing the carotid arteries and jugular veins in the neck. The calculated impedance of the wet head was 296 ± 21 Ω. The results showed that the application of 100 to 400 mA failed to stun some birds and some others regained consciousness before death occurred from bleeding. After a 600 mA stun, however, all the birds were rendered unconscious until death occurred. At this intensity, the birds showed mild clonic convulsions after the tonic phase, and then an exhaustion phase. None of them were killed by the current application. Therefore, to ensure a human slaughter in force-fed ducks, a minimum head- only stunning current of 600 mA followed by severance of all the major blood vessels in the neck would be recommended if the preliminary results obtained in the present experiment are confirmed. duck / head-only stunning / current intensity / welfare / spectral analysis