I don't see why people care so much, honestly. The vast majority of these animals are killed humanely, only a small percentage happen to go through this, and honestly, shit happens. You fix the problem after.
And just to bring up the post that said human rights and animal rights don't compete with each other, we could use the time and money used to enforce stricter regulations on these slaugherhouses on something that affects humans, for example, enforcing stricter safety regulations on factories or really any sort of dangerous profession.