Because of your geographical location (Illinois), I am doubtful that eye worm is the problem. But, all possibilities must be excluded, so please do check the eyes, as
azygous, has suggested. In today's transient lifestyle, there is always a possibility that this parasite could be brought into your area.
I am assuming that Veterinary care is not an option. Anyone will tell you internet doctoring, has a lot of room for error. Having said that, here is my input.
If no eyes worms are found:
Treat the eyes with natural Epsom salts. Place one spoonful of Epsom salt in a cup of hot water and stir until dissolved. Use a washcloth to soak up the mixture and place it over the chicken's closed eyes. Hold for one to two minutes and rinse with clean water, gently pat dry. Repeat two to three times a week. Dab some VetRx oil, under the eyes and around the nostrils, and comb.
The yellow diarrhea suggests some infection in the body. Even though she is not sneezing, coughing, there is also, some upper respiratory involvement. Sinuses are causing the eyes to swell. Mycoplasma, Infectious Coryza is a possibility.
I believe the hen also needs some antibiotic administered. A penicillin of some sort. I prefer to use an herbal antibiotic. Always follow any antibiotic treatment (herbal or synthetic) with a course of probiotics for poultry, to re-establish the gut flora.
It is common for hens to become ill with a couple of things at the same time. Be sure to isolate the hen away from the flock, in a
warm place (75-80 degrees), preferably in a hospital crate or tub, perhaps in the house or garage. Make sure the hen can move away from the warmth, if she wants to. You must also, be vigilant that the other hens do not exhibit any similar symptoms.
She will need time to heal, especially if it is cold where you are.
Provide good supportive care:
- I like to add 1 tablespoon of Aloe Vera or Echinacea tea to the water. Steep a teabag of echinacea for 3 minutes in a cup of hot water. Pour into 1 gallon of water. Use for 7 days to boost immune system. Make a fresh batch daily!
- Feed her some cooked meat protein or cooked eggs, diced fruit, diced black or red grapes, fresh greens, cooked grains like: brown rice, wheat berries, oat groats, pearl barley, also some toast with butter is good. Always offer her moist feed daily.
- If she cannot eat at this time, you may have to syringe feed her. I have used Hemp protein powder made into a loose paste to syringe feed. You can also try wetting her feed and spoon feeding it to her. She may not be eating because she can't see. Hand feed some diced grapes to hydrate and boost appetite.
So, these are some things I would do if she was my hen. This is my best guess, based on what you described. Other members may have different advice, please consider these too. And do your best to give her a chance to recover.
The healing ability of chickens is always amazing me, especially when they have a some help from their keepers!
God Bless!
. I’ll tag some people who can help. 
