Hi! We noticed one of our 1 year old chickens acting weird so we brought her inside to isolate her…. She can’t stand and when I pick her up she can’t hold her head up and she keeps jerking her head.. eyes always closed not eating, hasn’t laid an egg in days. Crop is empty, not really pooping, vent looks good and no injury whatsoever. She’s just barely moving. What should I do or what would of caused this. All our other birds look and act fine and continue to lay. My fiancé noticed one other one is starting to do a weird head movement tho