Why is the Gemara (Talmud) Chulin which talks about Ritual slaughter of animals not having to do with sacrifices in the Beis Hamikdash (temple) in the SEDER (order) of Kodshim which is talks about Temple sacrifices?
Rambam (in the introduction to his Commentary on the Mishnah) says that it is because the Torah itself introduces the concept of slaughtering for nonsacred purposes immediately following the rules about sacrifices (Deut. 12:11, 15).
It may also be due to the fact that kosher slaughter is basically an optional mitzvah (you don't have to eat meat), except in the case of sacrifices - so the topic naturally fits here more than anywhere else.
I would add as an answer, that perhaps, as the Torah describes within the context of wandering in the desert, animal slaughter without the context of sacrifice should be looked down upon.
See Vayikra Chapter 17:
1 And HaShem spoke unto Moses, saying:
2 Speak unto Aaron, and unto his sons, and unto all the children of Israel, and say unto them: This is the thing which HaShem hath commanded, saying:
3 What man soever there be of the house of Israel, that killeth an ox, or lamb, or goat, in the camp, or that killeth it without the camp,
4 and hath not brought it unto the door of the tent of meeting, to present it as an offering unto HaShem before the tabernacle of HaShem, blood shall be imputed unto that man; he hath shed blood; and that man shall be cut off from among his people.
So in essence, I would answer that Chulin, really is Kodshin. There are some chasidic stories regarding the holy purpose raising an animal by eating it as well.