I have a flock of 16 hens, one rooster. Most of the chicikens are 1.5 years old, and 2 are 2.5 years old. They were treated for coccidiosis at about 4-6 months I'm in Missouri and it's very cold here right now (freezing temps but no snow). Chickens were out today, and I did not check in the coop until tonight when it was time to put them up. One of the hens was laying on the floor. she has no wounds, her comb is red, her feet are normal color. She's just twitching every few seconds. I checked her vent to see if she was egg bound and I felt no eggs. I felt her crop and it feels normal to me, but not sure, it's kind of hard to tell as she's lathargic and not holding herself up like a normal chick of course. I'm having a hard time telling what I'm feeling. Any ideas?