You know, nicole, I had a somewhat similiar situation a few months ago. Had two ee pullets who had just started to lay, one went downhill fast and died. no easily identified symptoms - just noticed something wasn't right, next day she was dead. Her best buddy, who had been protected by her, started to go downhill a few days later. I had her autopsied, and the findings were that she was stressed from picking, and had a resulting overgrowth of e coli.So....the the little Fav pullet didn't make it through the night, DH buried her this morning. Could not get a stool sample, and DH did not want me to cut her open. Sending stools for the rest to a friend in Vet tech work to look at, just to make sure nobody has anything (I couldn't see anything, but a second opinion is always good). The others are all eating like mad and growing like weeds though. This little one was very close to the one killed, since she kept the Fav from getting picked on too much. Thank you again to everyone who offered help.
those two ee's were in a group of 4 pullets I added to the flock, and were smaller and less agressive than the other hens. Two of the 4 were roos, so I got rid of them, and that left the two . the biggest bully was the lowest hen on the totem pole in the original flock, another ee.
Not sure it that will shed any light on your situation, but I am truly sorry for the loss.