Hi, it sounds like you have to change her kibble, the fat is very high 20%min so max fat would be about 22-23% fat, she may not be able to handle the higher fat now she’s getting older…I looked at the ingredients in the Performance & there’s fish meal & dry egg maybe one of these ingredients she has become sensitive too, my boy got real bad diarrhea on the Eukanuba FP Fish & Potato, I blamed the potatoes it could of been their fish….
My boy has IBD & the only kibble that worked for him at the time was vet diet “Eukanuba Intestinal” fiber is only 1.7% & fat is 10%, the Eukanuba Intestinal is a low residue kibble so it breaks down pretty easy, so less work on the stomach & bowel….Eukanuba Intestinal has dried chicken & turkey & less fiber…… the Iams Intestinal Plus low residue has chicken by-products meal & fish meal & higher fiber, I wouldn’t try the Iams its made North America, where Eukanuba Intestinal is made Switzerland..
Sometimes when a dog eats the same kibble for years they can have an intolerance to an ingredient in that kibble…. if you don’t want to try the Eukanuba Intestinal, I would look for a limited ingredient, lower fat kibble, I always recommend the “California Natural Lamb & Rice” cause it has just 4 ingredients or there’s “California Natural Chicken & Rice” with 5 ingredients, if she does good on the Lamb & Rice then also buy the Chicken & Rice & rotate both kibbles so she’s having Chicken & also Lamb in her diet… here’s their link http://www.californianaturalpet.com/products still feed the cooked chicken & rice for breakfast or dinner & feed the kibble for the other meal, so she is having variety in her diet, not just the same food…I was cooking once a fortnight & then freezing the meals…
