What’s wrong with my chicken?

Several of my other chickens died of what I believe is Newcastle Disease. When this gal got lethargic, I figured it was that again. However, she has some strange symptoms that are different than the others. Her backside is swollen and red/yellow, and she is standing in the strangest positions. Y’all please let me know if you have ever seen this before or if it looks like Newcastle to you. She has had green diarrhea as well. Also she’s all wet because of my never ending battle with mites. Infinite chicken baths and weekly coop cleaning has been my life for about a year now.