My previously hardy and healthy RIR hen was panting a little yesterday, she was drinking but wanted to stay in the coop. When I checked on her a few hours later she was out foraging and seemed better. Today I came home from work, opened the coop and there she was.. Gone. Does anyone have any ideas what could have happened? Looking her over I saw nothing unusual. Also- this leaves just one adult (7 mo) hen left. What should I do now? Will she need a companion? I currently have 3 Rhodebars and 2 Swedish Flower hens but they are only 4-6 weeks old, they are in a separate part of the same coop. They can all see each other but are not in the same area. Is this enough company for her or should I get another girl closer to her age?