<----- personal opinion from myself
Orijen is a chicken based formula. I have heard a few things about the chickens being used currently, and I won't use a purely chicken based at the moment, which is one reason we went OFF orijen.
Natural Balance is good if you want to go ahead and try to figure out if you can narrow the allergy down. Their grain-free foods are in a safe range of Calcium and such, and each food is a single protein source. You can use this for elimination. My only thing is, our pup is active, and wanted more meat based, and natural balance's #1 ingredient is Sweet Potato..
ALSO, we use Canidae grain free... ALS grain free is all kinds of protien sources, but ALS grain free salmon is just fish I believe...
~Kristi in Virginia Beach
Mommy to my 8 year old son... and
~ Cullen Vom Sandstranden, Purebred GSD, Black/Red Male : 12/16/09
~ Panzer Vom Sandstranden, Purebred GSD, Sable Female : 11/29/10
~ Gizmo , Amstaff, Brindle/White Female : 5/5/2000