The symptoms you describe, with the blue comb/distended abdomen are often associated with ascites (fluid build up in the body cavities) and also possible heart or other circulatory problems as well. One can cause the other: ascites can be due to several different major illnesses and the fluid buildup can result in poor function of the heart and other major organs. On the flip side, a heart problem or other major organ disease can in turn cause ascites. The poor circulation results in the bluish comb. Tumors/cancers can also have the same effect. The ascites is also a common side effect of internal laying issues. None of these ever has a good outcome.
Another consideration: Could she be carrying a heavy load of internal parasites? Are they on a regular deworming program?
