not sure whats going on with a chicken

[mammajenn4]

So my family just adopted several chickens, a rooster, ducks and some Rabbits. One of the chickens came to us with a slightly red butt and missing some feathers and yesterday noticed that her lower back is missing a lot of feathers and her vent area is real inflamed and she is having troubles laying eggs. any ideas? She is a couple years old, still roosting but slightly lethargic. slightly runny poop a brownish slightly mustard yellowish in color.
Thanks

 

[loveourbirds]

im guessing its vent gleet, here is a link that may help.
https://www.backyardchickens.com/a/vent-gleet-aka-nasty-chicken-butt

if this doesn't appear to be right, post some pictures if possible.

 

[Eggcessive]

Some of her missing feathers may be due to feather-picking by another chicken. Vent gleet can be due to having other diseases as well. After cleaning her bottom and letting it dry, apply some Nustock or miconazole cream daily. Give her probiotics in the water or a small amount of yogurt (1 TB) 3 times a week. ACV in the water would also help. The yellowish stools could be normal cecal poops, but it also could be a symptom of E.Coli or blackhead. Posting a picture of the droppings would be helpful.