What caused ralph to be excited about hunting in chapter 7?
Ralph didn't want to go hunting at the start of Chapter 7; in fact there was a conflict between him and Jack over hunting, as in Chapter 4 the hunters let the signal fire go out while they were chasing a wild boar, and missed a chance to be rescued.
However, in Chapter 7 Ralph does join in the hunt and manages to hit a boar (though he doesn't kill it; unlike Jack, Ralph is not a real hunter). He now feels excited because he has achieved something and the other boys look at him with "new respect." This is the last moment where Jack and Ralph have something in common; for the rest of the book they will go further and further apart, with Jack becoming a "savage" interested only in hunting and fighting, and Ralph trying to maintain reason and "civilization."