Yesterday when I put up the hens I noticed one wasn't on the roost, but sitting on the floor in the hay. She was a little lethargic looking, but I had to go to work. I looked up backyard chickens at work and saw someone said to hold them upside down and see if stuff drained out of the mouth. This morning when I let them out, she was sitting in a corner by herself. I picked her up and her eyes were mostly closed and she was breathing slowly and had a couple drops of yellowy water stuff in her mouth. I turned her upside down and a bunch of stinky brownish water drained out. I did this several times and then had her sitting on my lap and she jerked around a little then died.. I just cleaned out the coop and I'm going to clean the waterer with bleach, but I'm worried about the other birds. They are acting normal, but so was she a couple of days ago. Any ideas?