I have gotten help with what appears to be a sick chick (original thread: https://www.backyardchickens.com/forum/viewtopic.php?id=523696) and am hopeful everything will turn out well. But while looking in on her I had the thought that even though she looked tired she didn't appear to be in any pain. I then realized that I didn't actually know what a chicken in pain would look like except one that was peeping loudly and constantly. In a general sense, how do chickens actually react to pain? Do they always just peep or vocalize loudly? If not, is there any way to tell if a chicken is in pain just by looking at it?