I read a sess/kag story where in one chapter, Kagome was in the woods with Sesshomaru (I think they were traveling somewhere) and he tells her to stay in one area while he goes hunting for food, well she doesn't listen to him and she walks off anyways. She's soon surrounded by pig demons and she kills most of them before Sesshomaru comes back and the pig demons run off. I don't remember what happens after that, but I do remember that later in the story, this Pig Demon Lord wanted to go to war against the West because some of his kind were killed on Western Lands (by Kagome). That's not really the main plot but those are the only parts I remember.

I swear this is going to drive me crazy. Any help is appreciated.

Sounds like Peace Treaty by piratequeen0405, rated MA. The scene you're describing looks like the one in chapter 08.