The first one I think was egg-bound. I found her dead near the nesting box. The body didn't look sick in general.
But (unrelated) a few days later I found a white leghorn sitting really still. At first I thought nothing of it. Mine often nap in the dirt or grass, laying in the sun. But then I noticed that her huge comb was bent over and dark in color. When I picked her up, she didn't move much and her eyes didn't change with the sun light. Then the really strange part: white-yellow liquid just poured out of her mouth. Then a few moments later, more poured out. Then again a little bit later. (All this time I was holding her, examining her.) It was obvious she was pretty much gone... alive, but barely, so I had my husband put her down. Whatever she had seemed to hit her really fast, as I didn't notice her looking the least bit sick the day before.
Any idea what caused it?