So I am a new chicken owner. Well about a month ago we got some older chickens from a friend. So I dont know how old they are. The chicken in question is a white chicken with quite a big comb. Well yesterday we noticed she wasnt feeling to good. Just kind of sitting there and didnt want to move. Well I put her in the coop thinking it was because she was cold. Well this morning notcied she was acting the same. So I isolated her and gave her a blanket because she was shaking. She was also breathing really hard with her beak open. Well I get her water and feed and come back to her and she is laying on her side with her head hanging down off the pillow. I tried getting her to drink and next thing I know she starts flopping her neck and head around and plops back down. Then she died. Beak open eyes closed and the light greenish yellow stuff coming out her beak. I have no idea what she died from. Anyone have any ideas? And if so, are my mother chickens going to get sick and die to? Im just so lost right now.