I've never personally witnessed the slaughter of an animal (except pheasants, partridges, pigeons, rabbits and hares, by shooting), but I lived, for many years, about 100 yards from a traditional abattoir, and I've seen video of a sheep subjected to Halal slaughter.

In the case of the abattoir, the cries of the animals were heard all day long, and they were clearly cries of terror, not the usual sounds you hear from cows, sheep,and pigs. The terrified cries stopped abruptly - presumably when the animal was stunned.

The video of the Halal slaughter was very different, the animal did not appear unduly stressed, the slaughter men were very gentle and spoke softly to the animal before and after its throat was cut. It appeared not to know what had happened to it, it didn't cry out or struggle, and it was held and gently lowered to the ground as it lost consciousness. 'Respectful' and 'kind' are the two words that sprang to mind as I watched the video. Not claiming that all Halal slaughter is performed in such a gentle, humane way - I don't have that much experience.

No judgment intended here, just my experience (such as it is).