It looks like she might have a small prolapse or just a loose vent. Perhaps others have been pecking at her vent, especially if they see the red. The pictures are not the best, so if you are able to catch her and get new ones that might help. A prolapsed vent or cloaca, can happen with straining from a stuck egg or poop, or low calcium and if the red tissue stays out and dries out, it can become necrotic or dead. If you can catch her after she roosts for the night or sometime today, I would look her over, and possibly give her water, a half a calcium or tums tablet, and keep her in a dog crate with food and water, but left with the other chickens in the coop or run for a day or two. Make sure that she can poop, since a stuck egg can prevent that. Honey, sugar or a lubricant such as coconut oil can be applied to any red tissue that stays outside the body to help keep it moist until you can push it back inside.