Oh god I hear ya! Ranger has been on Orijen fish since July and he just started getting gassy about a month ago. It's brutal the stench that dog can make! I'm opening windows in -30 weather to get the smell out and lighting scented candles like a crazy woman. I've added some probiotics/enzymes/fibers mixture to his food and it's made a huge difference. Instead of gas a few times a day, it's a few times a week and usually not nearly as stinky.
One more thing: I found the days I didn't take Ranger for a long walk (or a walk at all, I'm so bad) - he was waaaay more stinky. I'm not sure if it's because of an "inactive" dog plus the high protein content of the food but it's definitely a pattern. He wasn't gassy at all in the summer/fall when we were out on walks/runs for 1.5 - 2 hrs a day. Now we're lucky to get out for an hour and the days we don't, I definitely pay for it. Just a thought - at least it forces me out the door most days!