How can it be confirmed that the sheep did not die from electric shock prior to slaughter, and is there a specific sign for that?

If electric stunning leads to the death of the animal before it is slaughtered, then its consumption is not permissible. However, if it does not lead to its death, and the animal is subsequently slaughtered immediately according to Islamic law (dhakāh shar‘iyyah), then it is permissible. The International Islamic Fiqh Academy has stipulated conditions for non-lethal electrical stunning of animals: the application of the two electrodes to the temples or forehead, a voltage ranging between 100-400 volts, and a current intensity between 0.75-1 ampere for sheep and 2-2.5 amperes for cattle, for a duration ranging between 3-6 seconds. It is not permissible to stun poultry with an electric shock, due to proven instances of a large percentage of them dying before slaughter. The sign that the animal did not die from the stunning is the flow of blood after slaughter.