With symptoms only being noticed within a day or two, I am inclined to suggest to wait and observe. She could just have some crop issues. Have you had high humidity? Cold weather? It's easy to jump to the worst conclusion any time a bird does something different. Most of the time, it turns out...
I looked up the VermX and it seems to me it's used to support gut health. I didn't see any claims for deworming.
https://verm-x.com/products/verm-x-original-pellets-for-poultry-ducks-and-fowl
https://verm-x.com/products/verm-x-original-liquid-for-game-birds
Based on your description, I can't...
Question: You treat monthly for worms? What is your treatment?
How long has she been mouth breathing? *Usually* they'll frequently shake their head with gapeworm.
Mouth breathing can occur if they are stressed, trying to lay, overheated, or a respiratory infection as well.