It looks like there are some dried droppings and urates below the vent, but the jelly-like liquid coming out of the vent might be dropping, but there could be some albumen or eggwhite. Has she been laying eggs recently? I would insert a clean finger (use a disposable glove if you wish) into her vent up to 2 inches to feel for any egg shell, membrane or an egg. Is her tail held up or down?
That is good that her tail is up and it doesn’t look like egg whites. I soak her bottom in a bucket or dishpan of warm soapy water, and rub off the soiled vent. Dry her well, and make sure there are no maggots or other abnormality. Look for any lice while looking around. In warm weather, maggot larvae may be deposited on soiled vents by flies. It can be a deadly condition. Just something to be aware of.
Diarrhea can have a number of causes, from drinking more water, to a change in diet, worms, coccidiosis, or something else. Probiotics or some plain yogurt or buttermilk can be added to food to help.