"Do you think from your perception that the birds have a sense of what is going to happen to them."

Answer

"Yes. They try everything in their power to get away from the killing machine and to get away from you. They have been stunned, so their muscles don't work, but their eyes do, and you can tell by them looking at you, they're scared to death." (Virgil Butler, former Tyson slaughterhouse worker).

Hadhrat Maulana Ashraf Ali Thanvi (rahmatullah alayh) has explained that electrical shocking and stunning merely render the chickens immobile. Whilst their muscles are incapacitated, they are fully conscious and perceive the horrors to which they are being subjected to.