I'm going to disappoint with my recommendation, and I'm very sorry.
Your hen has a prolapse vent, either caused by straining to pass an egg or to poop. Sometimes the extruded organ can be tucked back inside, but your hen has been bleeding a lot, and it's probably from the other chickens nibbling on the prolapse.
It's not only been exposed to the environment, but it's been severely torn from the others attacking it. It's too damaged to restore. Your hen is probably already suffering from it being infected. I don't think a vet can do anything. So, I recommend putting her out of her suffering.