Dark soiled rear and red, raw, featherless belly on new hen

[KYChick13]

So I just adopted some hens from someone on Craigslist who needed to rehome and didn't notice this issue until I got her home.
The white hen has very dark, near black stool or diarrhea stuck to her vent area. Her belly is completely red, raw, featherless and looks just awful. (Couldn't get a pic of it as she is a bit spooked right now.)
Is it a sign of disease? What should I do to treat her and help her heal?
Attached pics of her and her two flock mates. I was told they are about one year old. They have some missing feathers not sure if it's from molting or pecking. The white ones leg scales look a little rough and peely.
They were kept in a small outdoor cage that did not appear to have a roosting bar but had elevated milk crates that may have doubled as a roost / egg laying box.
The floor was straw over a layer of DE. Lots of flies, and stinky. Maybe the red skin is due to irritation from the flooring?
Not sure if this is relevant to treating the hen, but there were rat turds in the food the previous owner gifted to me.
I am hoping I didn't just adopt a bunch of problems that will negatively impact my pullets and cockerel.

 

[dawg53]

Rat turds carry all kinds of diseases that can infect your birds. I suggest that you discard the contaminated feed and provide them fresh feed and water.

Keep those newly acquired birds a good distance away from your existing flock in quarantine. They could possibly have diseases or parasites that can and will infect your original flock. Poultry diseases can be carried on your person, including shoes, that can spread to your "clean" flock. It's called Biosecurity.

As for the new birds; inspect them closely for external parasites, lice/mites, especially around the vent area. Look for lice eggs attached to feather shafts. Dust them with Permethrin dust. Coconut oil will remove lice eggs. Worm all your birds with Valbazen liquid cattle/sheep wormer or Safeguard liquid goat wormer. Inspect all 3 for scaly leg mites. Purchase Nu-Stock at your feed store and apply the Nu-Stock on the legs and feet. Wear disposable gloves when applying it. The Nu-Stock will take care of scaly leg mites in no time. Put a light coat of Nu-Stock on roosts.

Wash off the rear end of the white hen, dry well, and apply Nu-Stock to the red/swollen areas on her rear end and underside. The Nu-stock will heal the areas and prevent picking at the same time. Also, when washing off her rear end, look for maggots and remove all of them if she has them.

In addition to fresh water and feed, give the newbies two drops of Poultry Nutri Drench orally twice a day for no more than 5 days. You can add plain boiled white rice into the feed you're giving the white hen that has the messy bottom. The white rice will settle her innards and help prevent diarrhea.
Do away with DE if you have it. It is useless.

 

[Vickischics]

Congrats on saving the flock. I agree with everything dawg53 stated. Well said.

 

[KYChick13]

Thank you so much for the advice and instructions!

 

[KYChick13]

Update, her belly is no longer raw and red, just bare and pink! I soaked her bottom to loosen up the dried on poop and worked it loose, she is looking soo much better, but not real happy with my messing with her. I am waiting for some of the recommended supplies to come in the mail since Tsc didn't have them in stock. Thank you again for the advice and support!!

 

[NorthwoodsChick]

Welcome to BYC! So hlad you joined, but even more glad you rescued these birds. You have a good heart

 

[APK]

Seems like you have done the right thing. I was going to suggest giving her a good bath with luke warm or less than luke warm water and let her soak in it for a bit, remove all manure and dirt attached to feathers and check for exposed wounds and fly strike. You can then clean the affected area with a cotton swab soaked with 1:10 dilution of Dettol and protect the exposed red skin with a little bit of Polysporin or Vaseline.

To determine if she has digestive issues you should check her poop and keep her separated to see if there is diarreah. Definitely use good feed. Properly formulated commercial layer feed and fresh water is all you really need.

 

[Wyorp Rock]

Update, her belly is no longer raw and red, just bare and pink! I soaked her bottom to loosen up the dried on poop and worked it loose, she is looking soo much better, but not real happy with my messing with her. I am waiting for some of the recommended supplies to come in the mail since Tsc didn't have them in stock. Thank you again for the advice and support!!

Glad to hear she's improving!

Keep us updated on her progress.