Yesterday afternoon I went out to the run to let out the girls for their daily free ranging time. After opening the run, I shut the pop door so that the hens will return to the coop when dusk sets in. Laying under the ramp to the pop door I found my 1 1/2 year old Speckled Sussex hen, dead. She had been fine when free ranging the previous day, went outside in the morning with the rest of the girls when I scattered scratch and BOSS...No signs of any animal getting to her. She looked like she had been sitting under the ramp then just died. I looked at her vent area, no signs of discharge or swelling. Anyone have any ideas what would cause a seemingly healthy bird to just die? This is just my second summer of having chickens, so this is the first non-predatory death I've had to deal with.