You actually don't have to use grains AT ALL if you prefer not to - they're really just a filler, cause allergies, and aren't all that easy for dogs to digest.
I've read Pitcairn - and I'm not all that impressed. The fact that he actually recommends grains made me question his expertise immediately. I homecook, but only take bits and pieces from Pitcairn.
After a ton of research, I found the MOST informative piece on dog nutrition is Orijen's White Paper - I use their dry food for day grazing (btwn cooked meals). This paper is truly AWESOME.....and, it's not so darn overwhelming bc it's simple to understand. After reading this, I finally, finally felt confident in what I was feeding/cooking/doing bc it made me understand canine nutrition.
http://www.championpetfoods.com/orij...hite_paper.pdf