Greetings, I am Dr. Pat. I have worked with birds exclusively for many years.
LIFE THREATENING EMERGENCY AND THE BIRD NEEDS TO SEE A VET IMMEDIATELY.
Can you upload a photo?
The most common thing that causes this is an egg or other reproductive Problems. GI issues, tumor, kidney disease, metal toxicity, calcium deficiency can also cause cloacal prolapse. Regardless of cause, it is a LIFE THREATENING EMERGENCY AND THE BIRD NEEDS TO SEE A VET IMMEDIATELY. Chance of perforation, peritonitis, tissue damage and toxicity, pain are all very high.
A bird experienced vet will be able to find out what is going on and be able to replace the tissues in a proper manner.
Where are you located?
Use saline or even artificial tears (for humans) to keep the tissues moist. DO NOT use anything else or try to push things back in.
Your job is to keep the bird warm, safe, quiet, and confined; and to provide adequate hydration and calories.
Move the bird to a box or carrier with soft towels in the bottom, no perch, and food and water in low bowls that can be reached easily. Put the whole thing on a heating pad on low or medium. Check it frequently, no overheating allowed! Keep the unit partially covered, warm and quiet. White paper towels or white cloth towels will show the true color of the droppings. Small animal/reptile boxes are great for this purpose.
The bird, bowls and unit must be kept very clean.
Here are some helpful links:
Again, THIS IS A VETERINARY EMERGENCY
I really must stress that you need a bird-experienced person, and not just a vet who advertises that they care for birds.
You need to take your bird to see an avian-experienced veterinarian ASAP for complete examination, diagnosis and appropriate treatment. Check
https://aav.site-ym.com/?page=basiccare click on "find a vet"
for members of AAV in your area or call your regular vet and see who they recommend; ask if they really have worked with birds a lot. Unfortunately, this list does not rate competency or experience, but is only a starting place; the vets at least take the avian medicine journal and hopefully see a bird or two a year. The best referrals are word-of-mouth, so check with several non-bird vets, the humane society, parrot rescue groups, bird clubs, etc. for their input. As you might guess there may be controversy and varying opinions even with this. Even board-certified avian specialists may not have a lot of practical bird experience. Unfortunately there are few resources available to refer you to really good, clinically-experienced bird vets.
Ultrasound is often more informative than radiographs and does not require anesthesia (ask your vet about this option). But some kind of imaging is essential to see what is going on, and what damage might be happening.
If there is an egg, it all depends on the bird's and the egg's condition what the next step will be. Same with the exteriorized tissues.
If this were my patient, and money no object, I would start with complete fecal analysis and direct smear, stained with Sedi-stain and unstained for multiple parasites, fungi, spirals; direct smear stained with Sedi-stain and unstained of the oral cavity; bacterial culture and sensitivity of the feces and choana. Depending on the case I might do a fungal culture. Routine blood work is necessary to rule out other issues. There are MANY DNA/RNA tests for bird diseases.
Generally I start them out on medications as indicated by the tests.
AAV recommended lab work
Your bird will need injectible fluids, calcium, antibiotics and many other medications. Act quickly and good luck.