I don't know what could be wrong with her unless she's egg bound or something like that. She was fine when I put her in her pen today at around 4:00pm. She didn't lay an egg today, and she usually does every day, there have been a few times that there wasn't an egg in there, but she usually free roams. Today we didn't let her free roam since her sister got attacked a couple of days ago and we were scared to let her out, but I did let her into another pen by herself for a while today, and she was doing fine, the whole time. I was watching her outside my door. I did have to catch her in the net to put her back, and it did scare her, but didn't hurt her at all. She was fine when I put her up. When I went out about 30 minutes ago, she was not on her roost as usual and was down on the floor acting like she couldn't walk, and is breathing very hard. She had some poop stuck to her back end, and it was white, but was normal looking to me, and was not stopping up her butt, but underneath it. I cut it away. Her butt is breathing hard too! I tried to feel and see if I felt anything lumpy or anything in her stomach or anything but I can't tell if anything is wrong. What could it be to have affected her that quickly just since 4:00 this afternoon. She seems hot like maybe a fever. Does anyone have a clue what it could be. There are no sick chickens here that I know of. We don't have many and they all free roam. I did notice that she sneezed today once, but didn't think anything of it. I did put her in an area where other chickens have been before, but these same chickens go all over the yard and so does she. And it's a pen that usually stays open where chickens just go in and out, none usually just stay in there. Could she be affected by being in that area today, that quick? Really need some help quickly. She is not sneezing or runny nose or anything except breathing hard and won't walk.