In the last two weeks I have lost three of my seven hens. First sign was that when I was using eggs, I started to see some with a clouded semi-opaque white, as if partially soft-boiled. Then, within 4 days of noticing this, three of the seven were found dead over a 48-hour period, no abnormal marks or colorations, butts intact, no injuries. I am of course worried about the remaining four. Any idea what this illness is?