I am new to keeping chickens ( i started one year ago and i have never heard or come across anything like this before) Two weeks ago I noticed one of my hens losing a lot of weight and she would almost fall over if something lightly bumped into her. She was eating and drinking well but when she wasn't eating or drinking she was always under the heat lamp all fluffed up. After about a week of trying to get her better ( feeding her food by hand to make sure the other hens weren't bothering her, giving her meds to try to boost her immune system, and stuff like that.) she died. ( her comb was dark purple/blue but she didn't seem to be in any pain and when I picked her up the day before she died she felt as light as a feather) I have no idea why she died and I feel very sorry that i wasn't able to get her better Since then I have been checking the other hens and one has the same symptoms as the hen that died. Does anyone know what is causing this?? And can I save my hen? What do I do??