I have a hen that I believed to be a prolapse. She was just not doing well at all and I brought her inside. I don't know if it got better on it's own or if the combination of things that made her better. I gave her an antibiotic that I picked up at the feed store along with a soak in Epsom salts and used iodine on her bum. I'm on day 4 of antibiotics and she's doing much better and has since Monday. Without have a fecal sample tested I have no way of knowing what caused her vent to pop outside of her body, but on maybe Sunday I put her on top of the puppy crate I had her in to basically watch her vent. It was disgusting, but I wanted to see the process of her passing stool with her vent out like that and I'm glad I did because I saw what looked like the left side of her vent swollen and as it came out even more and I saw what looked like a pustule. It reminded me of a canker sore. Whatever it was could possibly have been the source of the swelling and prolapse. The Terramyacin may have cleared it up.