Actually Wendy they have been flip-flopping for most of the season... Last weekend they played Rock and Roll Part 2...

I haven't really gotten any clear answer from the Pirates staff that I have talked to on the reason behind the flip-flopping...

To be quite honest, R&Rpt2 is more of a staple in hockey than any other song... Bro Hymn (the song you are talking about) is nice, but it is more Anaheim's song than Portland's. I am all for supporting the parent club, but not when it comes to sacrificing your own individuality...
But in the last few years there has been a shift in the hockey circle. Management has moved away from the song, which has as much to do with team originiality as it does the pedophile history of the song's author Gary Glitter.

On several forums I frequent these changes have not been embraced with open arms. Some like the familiarity of chanting "Hey!", others acknowledge the nostalgia the song has with the Pirates, and others site the fact (as I mentioned above) that Bro Hymn is Anaheim's song and not our own...

Personally I prefer Rock and Roll Part 2...