Have 5 hens, all 7 1/2 months old. Very healthy, active, laying well. This afternoon I was bringing them in from ranging the yard and noticed my white Rock missing. I found her standing in the driveway and shooed her into the run. She immediately sat in the straw and when two others pecked at her she didn't flinch. I picked her up and other than breathing thru her mouth, she seemed fine. Her color was good, comb up, vent clean, didn't seem egg bound (she laid yesterday). I put her in the coop where it was warm. I checked on her about 30 minutes later and she was gone. Any ideas? I'm stumped.