limping red vent naked neck

[theartsypaul]

I noticed she was limping. Looked under foot for a thorn or something and it looked clean and she didn't jump when I applied pressure. I then checked her vent for a stuck egg and nothing. I slathered olive oil all over her. She is still laying, but still limps. After I checked her vent she pooped and I thought maybe I went in her intestine not the egg tube, but I'm pretty sure she is laying. I've checked for mites and she has nothing that is not ordinary. She will move or hop but really just lays in the dirt. Fortunately the other hens aren't picking on her. I noticed the next day, after vent checking, she was all red and I thought prolapsed vent. How could something with the vent cause her the limp? More than one problem?