Petunia has had a poop problem for over a week now. It's all over her behind and I tried to clean her up a few days ago and the smell is so bad it makes me gag. I thought it might be the new food I was told to buy so I bought a bag of the original food to see if that would help. Today she is just standing there. Her poop is runny and yellow. I did get her to eat. I mixed up a batch of the electrolyte powder and probiotic powder and gently put her beak in it but she wouldn't drink. Her feathers are puffed up so she almost looks like a ball. She is a red comet and is 3 years old. Her two sisters are acting fine. One of them has a poopy butt but nowhere near as bad as Petunia. Could someone please tell me what I can do to help her?