So I came out this morning to my chickens and one had died. I couldn't believe it and I was so scared when I saw her laying under the raised coop and not moving. It was so unexpected. I hadn't noticed any weird behavior earlier, we had been getting eggs from her the last few days and I didn't see any parasites on her when I picked up her body this morning. She didn't seem skinny at all either. I was trying to look things up and thinking it might have been Mycoplasma gallisepticum or MG or whatever it is called. Her eye was closed and may have been swollen but it didn't look that unusual. The one thing I noticed this week was that when I let them out to free range her comb was a lighter color, more pinkish than red. I didn't even think anything at all of it and I know I should have. I think her death is at least partially my fault and I feel so so bad. I can't even begin to describe it. I know I could have been giving them more attention. What can I do to figure out why she died and prevent the rest of the flock from getting anything she had? Help very much appreciated. Thanks in advance.