Since when did frenzied boar boss packs spawn?

[ogot]

I haven't encountered them yet in single-player, but when I was playing my sorc in Hell mode, ladder (softcore, Asia1), trying to lvl up... I teleported right into a frenzied ice boar boss who was cold enchanted and lightning enchanted! Bam, explosion, frost nova, charged bolt makes one very dead sorc (well, mine, because I hadn't started working on my items that much, yet...)

And can they be found exclusively in Hell mode? What about the Black Raptor Nest boss packs? ( I haven't seen a single one spawn yet... Are they still around?)