My 9 month old Houdan pullet died today. 36 hours ago she was running around healthy and happy, laying eggs and thriving. Less than 24 hours ago, she was lethargic and not talking (she always had a lot to tell me and was very chirpy). I thought she was quiet because it was close to dusk and she was getting ready to roost, so I didn't realize until this morning, when she was still in the hen house after the rest had run out for their morning foray, that something was very wrong. I took her out of the hen house to get her in an infirmary box - her body felt stiff, her breath was fast and shallow, and I could swear she had a fever coming off her head. I know it wasn't an animal attack. I know it wasn't too hot or too cold for her because I live in temperate climate. I know that she didn't have any signs of illness (pox, diarrhea, etc). The other chickens are fine right now, but as I have no idea what happened, I have no idea what I need to protect them from. This was all very fast. I don't know if she ate something bad (all my hens eat the same and all free range in my yard), I don't know if she was egg bound (I thought she was regularly laying eggs and I couldn't feel any lumps in her belly), I just don't t know what else to do. Any ideas or suggestions? How do I keep my other girls safe?