Shamrock Farms is a U.S. company so that might be why you don't know about them.
People don't post so fast! I need time to edit my freakin posts!
Edit: shit, Shamrock farms is an Arizona company and ships to the Southwest.
You should still remember that milks with those stickers are possibly good. I gave a lot of info, and if you really want to know more about what milks are healthy and what aren't, I think you guys should do your own research : /