I just finished up a little research of my own and found Canidae has changed ingredients of the lamb and rice allergy formula. They've added cracked pearl barley, rice bran (filler?), peas, and millet. Their explaination is to lessen the worldwide pressures on rice, supply shortages, and rising costs.
CanidaeŽ Pet Foods: All Life Stages: Dry: Lamb & Rice: FAQs
As far as I can tell none of the other formulas have been affected.