Hi, I've had chickens on and off for years. They are kept in a secure coop that has a dirt floor, hay and roosting boxes. Predators can't get in. I bought four silkie pullets about 4 months ago. I also have 3 other pullets and a rooster. One of the silkie pullets weakened and died overnight about 3 months ago - pretty much as soon as I got them. Now I have one who has been just fine for 4 months until this morning. She wouldn't eat or move. She was sitting upright. Now, 4 hours later she is near death. What causes this? Everybody I know who has chickens says this just happens.