Kinda sounds like a bad joke… but in Germany they do.
They are being lowered into a pit in masses and then stunned using CO2. In theory (and propagated as such) a rather “good way to go”, but they tend to suffer a fucking awfully long time, because well… they’re being suffocated alive with a lot of them in a small pit. So yea…
Yeah, iirc TetraPak advertised as being an eco-friendly packaging and was prohibited to do so (at least in some countries, dunno) exactly because of that.