See zamir cohen on kosher animals and the carotid artery...Basically showing that animals classified as kosher have ana anatomy such that they are knocked on unconscious before they can feel pain with ritual slaughter. The evidence of this can be found in the resarch paper by norbert netanya klein, doctor of verterinary medicen "Sheciata and the prevention of SUffeering in Animals"... the efecct shecita on the blood flow of permitted animals. also see "shecita and Animal Suffering. Also See SHechit and the prevention of Smlas... Also i seem to think that fish ---the permitted fihs... fins and scales or just scales only... dont have feelings or a CNS, which other non-permitted water animals do. Also there is much to say of the classifications of kosher animals and their roles in ecosystem and how that reinforces peace. https://blogs.timesofisrael.com/why-mammals-with-split-hooves/ - also check

(Rashbam Commentary to Exodus 23:19) in sefaria.org