This morning, I let my hens out of the coop into the yard as normal. One of them, Lucky, stepped out and just stood there. Her comb was very pale and limp. I watched her for a bit and she never moved. She had yellow runny diarrhea. She wouldn't even eat her favorite treat (yogurt). I went to the local feed store to get antibiotics and by the time I got back she was lying on the ground panting. Within thirty mins, she was twitching and then she died! Anyone know what could have happened? She was perfectly fine yesterday. Thanks for the help.