The following info was found by a user on the discord, and it's all in their words

CW: animal cruelty, death, commodification, snuff

Here's a description from a sound effects library from a prominent site for audio professionals:

Terrifying squeals, grunts, barks, and sneeze from adult pigs weighing up to 400 lbs, and ambiences from the stables. The second part is recordings of smaller pigs (80 lbs) on the day they were picked up by truck to go you know where! The pigs knew exactly what was going on, which is represented in the sounds recorded. Needless to say, this library has been ear wrecking to put together, but the reward is 246 single files of pure pigs.

https://www.asoundeffect.com/sound-library/pigs-fx/?isp_ref_pos=1

This isn't a story. The link is to the store page for the library. This is something I just found. To the best of my knowledge, recordings of murdered animals and other forms of cruelty is an open secret in the audio industries. I haven't been able to find any evidence that someone else has written about it publicly.

If you're wondering why recordists would do this, this is how those recordings are used:

Bloodborne How to Defeat the Giant Pig Hog Like Monster in the Sewers - https://youtu.be/Za5wRpoVons?t=242

Lego Star Wars: The Complete Saga - Gamorrean Guard Death Sound - https://www.youtube.com/watch?v=GIUttgEdsxQ