Originally Posted by Goldens4Ever
How much time has elapsed between each type of food you've fed?? Please note that when dog consumes something they're 'allergic' to, those allergens can remain in their system for 3-6 months thereafter. So, if you're switching between foods within a short amount of time, it would appear that they're allergic to everything because they're still reacting to what was fed previously, or before that, or before that, etc.
The time has depended on his reaction to a new food. He was fine with my cooking his food for about 6 months - and that's the longest he was ever on any food - others have been 1 month or less, some 2 months. I did try going back to a food previously tried - after about a 6 month lapse - nope - he reacted to it almost immediately - within a day or two.