My quails have been doing great with their egg production. They got mites once because I took in another baby bird (of different species) without knowing it had mites, but I took care of it instantly. My quails egg production never went down, and they were laying strong, healthy eggs. One day, randomly, their egg production slowed, and I was getting only one egg. Now I am getting no eggs. One of them finally laid a single egg and it looked perfectly fine but when I cracked it open to give it to my dog there was no yolk and the liquid that came out was gray and green and gave off a horrible smell. I've tried looking up everything I can about rotten eggs and other reasons why the egg production diminished, but I can't find anything on what could be causing this. I've cleaned their entire coop and have given them fresh and brand new everything. Does anyone know why this is happening?