Hi
I'm sorry to hear your girl is poorly. How is she doing?
What breed is she? Generally it is larger breeds that are more susceptible to this disease. There seems to have been quite a few Buff Orps here on BYC with it recently which may suggest a genetic factor, but diet is an important consideration along with how you feed them ie gravity feeder available ad lib, feed scattered on the ground or fed from a pan twice a day with fermented feed, and how much space they have to roam and forage and get exercise and of course what treats are given. Scratch, corn, bread etc are main offenders for this disease in my opinion.
It is my belief that too much carbohydrate in the diet is the issue rather than fat, so a higher protein feed may help (more protein usually means less carbs) and the form of the feed may also be relevant. A whole grain feed or mash where birds can pick out individual components of the feed and selectively eat their favourites may be more likely to lead to this condition than a pellet or crumble. I'm in the UK so I'm not familiar with what form the product you mention comes as.
Fermenting feed might also be beneficial in a situation like this and I believe vitamin B complex is good for helping to support the liver. Decreasing access to food ie stopping ad lib feeding, scattering food and increasing area to forage may help her but I am not sure how reversible the damage is once you start to see symptoms.
I would say that you have probably been lucky to catch her before sudden death. What symptoms are you seeing? Ascites, respiratory distress, soiled butt, prolapse, hopefully not rupture?