When a person slaughters an animal or bird, he should think in his heart, this one that didn’t sin was slaughtered.…How then can a person who is full of sin escape the spilling [of his own] blood / sh’fikhut damim and Gehinom [purgatory]? And he should consider how the Holy One commanded him to cover an animal’s or bird’s blood, lest the angel [having] authority over them should say, “How can the blood of this one that didn’t sin be spilled by the hand of a sinner whose sin is like scarlet and worm” and [thus] he becomes sealed in the blood decreed for death. ~ Sefer Chasidim, sec.373 (R. Yehudah HeChasid, 12th century)
This entry is going to explore some of the implications and meanings of slaughter and kosher meat, including material from the columns I've been writing for Jcarrot.org. For now I only want to note again (as with Cordovero) that the mystics were quite ready to expand human ethical principles to include animals.
Jcarrot columns from Reb Duvid on meat-eating and animal slaughter: "Kashroots: An Eco-History of the Kosher Laws" – on Jcarrot.org
"Agro About Agriprocessors" – why t'shuvah isn't enough for Agri to be eaten, on Jcarrot.org
"The Meat of the Argument: Do Jewish Enviros Have to Be Vegetarian?" – on Jcarrot.org
There are many more entries on Jcarrot from other authors on these subjects as well.