Breadcrumb: Barbecue me a heifer!

In the case of many of the animal sacrifices, it was the one bringing the offering who killed it, after which the priest brought it to the altar and burnt it. (Lev. 1:5, 1:11, 3:2, 3:8, etc.) It seems clear why the latter should be the case: the altar was holy ground and off-limits to the common people. However, why should the common person kill the animal? Perhaps it was for cleanliness issues: the priest may not have wanted to get dirty. It might also be to ensure the donor didn't get cold feet and leave at the last minute. Or maybe it was just a way to get out aggression without negative consequences. We may never know.