I almost never say this in video games, but those boars are cheats. If I recall, there's five of them and they spam that charging move that gives you no choice but to roll and rolling in TW3 always causes a second delay for your follow up action. Stunning doesn't work great and without some kind of poison, bleeding, or burning effect on the boars it's difficult to do damage because of their movements. I didn't try Axii, maybe, similar to the giant spiders (whom I also hate), they're weak to Axii sign.