Can you post a picture or describe all of the symptoms? Vent gleet is not simply a poopy vent, but would be red, possibly with white or yellow patches, with missing feathers, and a bad smelling discharge that continuously runs. Vent gleet is usually a fungal infection of the GI tract. How does the crop feel, and is it emptying by morning? What are you feeding her? Is the belly below the vent swollen or enlarged? If the chicken was in an overcrowded area before you got her, feather and vent pecking may have caused problems. Using probiotics in the diet and a little plain Greek yogurt can help replace the good bacteria in the intestines. Keeping the vent clean, and using a cream such as Monistat or Nustock just inside and outside on the vent, may help. Clean water and feed are helpful.