This should be posted in /c/anime but I expect most people in /c/anime not being ethical vegans or even not having full visibility or answers.
The only series which satisfied me at certain point was Beastars, which I finished in manga, and I don't know any other series.
In the case of faulty animated series, Manga is also accepted in english at least.
Promised Neverland
I think this was from a perspective of the children being the livestock, right? I remember some of my classmates watching it on classroom computers while making a lot of jokes of the reactions of the children experimenting the death.
I watched it until second session in chapter 2. Emma ruins it, in the end everything is centered only in humans and the same is not expected with the other species.
Even with the issues that some demons have like the two killed in chapter 6 with their sister, the group have no thought of the possibility to not kill them. Seems this is a bit different for Emma but not for Norman and the same as above is maintained.
:'3
It's not anime but the animated film Plague Dogs covers the quest to escape an animal testing facility of two dogs by the people who animated Watership Down and it's sad as hell.
And literally that one quote from Ghost In The Shell 2: Innocence
“We weep for the blood of a bird, but not for the blood of a fish. Blessed are those who have voice.”
That's all I can think of. There are characters who mention they don't eat meat offhand sometimes, but that's about it. The people who make anime don't seem to want to ever actually touch real politics so you get maybe vague allusions at best.