I went out to the coop this morning to feed and water my 18 hens, and one was in a nest box dead. Her legs were outstretched, as if in a seizure . No outward signs of injury. She was 2 yrs old, looked healthy and was well fed. The hens have a half acre of free grass pasture besides the daily feed and water. We use TSC Dumore Layer feed and have oyster shells, dirt, soil, grass, bugs, weeds, water sunflower seeds etc. She was looking healthy up to this point. She laid very large brown speckled eggs. No other hens were dead. Any ideas of what may have happened? Her breed was something like Midnite Marauna. She was large, all black with feathered legs. We bought her at Tractor Supply 2 years ago.