I really thought the one with the shorter tail was a Cockerel! This is my first experience with chickens so wasn't sure. That one seems different than all the rest and has always looked different and seemed to make different noises. I really appreciate yours and everyone's feedback!
I am really sorry that this happened to your girl :( It sounds like she had an infection of some kind and developed vent gleet (poopy butt). Is she a large breed? They are much more sensitive to being held on their back.
I have had success reviving a very weak chick that didn't want to eat or drink by putting a little bit of egg yolk on the side of her beak. As soon as she got some of that, I also took a dropper and put a drop of water on the side of her beak, and she began drinking. It really helped her. I had...