My dog's poop has white fungus spores growing on top after a few days. What can this be?
What you are seeing is probably mold growing on the stool. It is normal for this to happen especially if it is humid at night and the stool is somewhat protected from the sun during the day. It may be related to the food change simply because some of the ingredients of the stool have changed with the food. It is important not to bounce around with her diet since this can cause her stomach problems if she doesn't tolerate change well. It would be best to find food that she does well on and just give her that.