We have a flock of 8 chickens, 3 years old. They have always been healthy, no problems. About a month ago, one chicken showed these symptoms: a bluish comb was first symptom but then turned back to red over next couple of days, protruding abdomen (very big), held her head in an awkward way, stood in a tall, stretched-out way, separated herself from flock, green poop, all over a period of about 5 days, then she died. Then a few weeks later we lost another one, but this one showed no symptoms, we just found her dead. Now we have one, just observed yesterday, seems to have large swelling or lump in neck, making jerky neck movements, standing still with eyes closed, stands in one spot separate from flock. Any help much appreciated!!!