Hello everyone, I am new to backyard chickens, and being that a mysterious event happened, I figured I would come here. We got 5 barred plymouth rock pullets a few months ago. we lost 2 of them to hawks, and this morning, another one.....only this one wasn't from a hawk. we have an older group of chickens who peck the pullets, so we made a day run for the pullets. the only time the chickens are together is in the morning and the evening. we have a ramp that leads up to a pass-through in the big coop run for when we let the chickens out to forage, and the pullets take refuge there either until we put them in the day run or until the big chickens have all gone up for the evening, when they come off the ramp and eat, drink, etc. then they go to bed. this morning, we came outside to move the pullets into the day run and our smallest one was laying on the ground by the ramp, dead. we checked her out, and she had no wounds, her body was not stiff, so she had just died, she was still warm, she had been eating and drinking normally previously, etc. The only things was that she had been very puffed up the past few days. Also, when we checked her out, her vent didn't look right. it looked like it had almost started to turn inside out or something. We wondered if she was egg-bound, but we felt her underside and we didn't feel an egg. She had been laying previously, and we also wormed the chickens fairly recently. Does anyone have an idea of how she might have died? Are the other chickens at risk of something happening to them?? What's going on?