One of my Rhode Island Red hens is rasping horribly. I found her sitting in the bottom of the coop Tuesday morning, immediately isolated her inside opur pump house, put a warming light on her (since it has just turned really cold here in Washington), and have been giving her antibiotics in her water since. She laid an egg on Tuesday, but not since and does not seem to be getting any better. She gasps for air whil raising her head with her beak slightly open. She shows some interest in food and water but not much. My other chickens and rooster are just fine. Anyone have any idea what is going on with her? Any advice would be greatly appreciated!