1. Separate chicken from flock
2. Clean protruding tissue well
3. Replace the tissue manually
4. Apply hemorrhoid ointment (without painkiller) on the inside and outside of the prolapse
5. Supply with vitamins, electrolytes, calcium for uterine muscle health
6. Consider antibiotics if area is pecked/dirty
7. If tissue will not stay in place consider applying bandage or diaper (instructions are also on the site, link on the page)
8. Monitor condition of hen over lifetime
Hope this helps.
Yes that looks to be a significant prolapse, probably with more tissue hanging out than with most I have seen in pictures. Can you apply some honey, sugar, or hemorrhoid cream to the prolapse, and when you push it in, try to hold it in for about 10 minutes while you hold her in your lap. About the only treatment is to just keep pushing it back in, keeping the area clean daily, and hoping that she will eventually keep it inside. Prolapse is common in hatchery hens due to their laying of large eggs almost daily. Egg binding can also be a cause. Placing her in a dark space for 16 hours overnight each day, and reducing the feed amount some can help. But, in some cases the large intestine can come out farther, and most chickens have to be put down. Let us know how she does, and I hope that you can help her.