http://www.the-chicken-chick.com/2012/04/prolapse-vent-causes-treatment-graphic.html
After reading your post / question... I did a search on prolapse and found this site that I will keep saved!
I literally had to insert a finger, find the egg and gently push it out, curving my finger around it and pulling it out ever so gentle cuz l didn't want it to break. She wasn't prolapsed as l remember looking at her vent which looked normal
I think the huge egg which she couldn't get out for over 24 hours plus the other egg still inside was too much for her...still brings tears to my eyes. I came up to these mts a city girl and am slowly growing into a country girl.
I keep a close eye on my other 10 girls, keep apple cider vinegar in their water which helps the poop ... Give them milk and yogurt for calcium along with other healthy foods
This website has been my "chicken bible" and l appreciate how everyone shares their knowledge, especially those who have chickens for years!
I was so worried abt them freezing up here but aft reading comments on here, am now comforted they will survive! Now as soon as my sons build a 8x12 wooden shack with roof and sides to keep them out of icy winds and snow... The coop will be inside the shack!
Good luck with all your feathered friends!