The red thing is her cloaca which is out a bit, and it is called a prolapsed cloaca or vent if it was out more. Put some honey or ointment on it so that it doesn’t dry out. She looks really dirty from soiling herself and her foot look st have scally leg mites in the picture, but also has poop on it. Get her cleaned up in a warm soapy bath in the sink or in a large dishpan. Epsom salts is good, but dish soap is fine. Then apply the honey or ointment to her vent prolapse.
Her position of the leg forward, and lameness could possibly be Mareks disease, but for now, I would just treat her symptoms and give supportive care. Offer her chicken feed made wet with water, scrambled egg, tuna, or canned cat food pate, but mainly chicken feed.