Welcome to BYC. I tend to agree with the others who are thinking that your BO may be suffering from a reproductive disorder, such as egg yolk peritonitis, internal laying, or even ascites (fluid in the lower abdomen.) Her droppings could be significant. Is there anything in the droppings that looks like “cooked egg matter?” Pictures of the droppings can help. The red material could be a bit of blood clot or some intestinal shed. I would concentrate on getting her to eat and drink normally, and keep her comfortable. If you should lose her in the future, you can find out what was going on by either getting a $20 necropsy by your state poultry lab, or do one yourself at home. With a home necropsy, you can take pictures of the abdominal organs, from the beginning when you open the abdomen, and also of the important organs (liver, intestines, gizzard, oviduct, spleen, etc.) We can have a look, and possibly give opinions. Here is where to contact in your state for a necropsy:
https://www.cdfa.ca.gov/ahfss/animal_health/pdfs/CAHFS_NecropsyFactsheet.pdf