We had a visit from a predator. One hen is missing (presumed dead, based on the feathers and a little blood.) I found our ameraucana about 75 yards away from the coop. She was just sitting in the grass, as if she were resting. When I went to pick her up, she didn't move, but she was obviously alive. I set her on her feet, and she walked a few steps and then fell over on her side. We quickly examined her and could find no obvious signs of injury. (We're fairly clueless about chicken anatomy, so this may not mean much.) We set up a cardboard infirmary with bedding and food and water, and she just sat there motionless. After a time, we picked her up and tried to get her to drink by dipping her beak in the water. She didn't respond at all, so my husband opened her mouth while I dripped drops of water in it. She did fine swallowing when we did it that way. I remembered reading that chicks that have had a tough journey should be given water with a little sugar to restore their energy, so we've been giving her a sugar water every hour. Her eyes are bright and she seems fairly alert. She isn't shaking or anything, but she's not used to being held, yet offers no resistance whatsoever now. Just now I took her out of the box and set her on a table to try to get a better look at things, and again, she just flopped over on her side and laid there--legs sticking straight out. It's only been about 5 hours since we found her, so I'm hoping she'll bounce back. However, I don't want her to suffer. Do chickens go into shock like humans do after a traumatic event? Or is it likely that she has an internal injury? How do you know when a chicken needs to be put down? This is very upsetting, but I'm trying to remain calm and rational.