I think with all foods you just have to run with it, its like us humans what one person can eat, another can't, trial and error really. We have foods we can't tolerate and I think our dogs are the same.
Coco was OK on burns to start off with, then he constantly had an upset tummy, so I put him of AG at first he was OK, but then I had a similar problem, so he's being barf feed and so far so good.