Luna's right eye is swollen today. I am wondering if she was stung or some sort of infection. What is the best particle for treatment. She is acting normal otherwise. Thanks.
I see dried blood below her eye, most likely she got pecked. It looks like her eyeball is still intact.
Gently clean the eye with warm wet compress. Or, you can flush the eye with a saline solution, in case there is any debris, then gently pat it dry with a clean cloth.
Apply terramycin ointment, or a triple antibiotic ointment, on the lower lid of the eye. You can use Neosporin (without pain reliever), but an opthalmic ointment is best. When the chicken blinks her eye, the ointment will spread over the eyeball. Apply every 12 hours, 7-10 days.
Purchase at feed/farm store.
Saline solution eye wash:
Saline solution, is sterile salt water. It can have different amounts of salt in it. “Normal” saline has about 0.9% salt. You can make it or buy it.
Making saline solution at home:
Get a clean storage container and mixing utensil. Either wash them in the dishwasher or boil them for 5 minutes.
Use 1 quart (4 cups) of distilled water, or boil 1 quart of tap water for 5 minutes. (Do not use well water or sea water.)
Add 2 teaspoons of table salt.
Mix the water and salt well until the salt is completely dissolved.
Cool to room temperature before using, if you boiled tap water.
Saline solution can be stored at room temperature in a tightly covered glass or plastic bottle. You can keep it for up to one week.
You will have to be vigilant that a secondary infection doesn't set in. If the chicken gets sleepy or lethargic, stops eating etc., you will have to treat with an oral or IM antibiotic.
These are my thoughts on your hen's eye. I hope they are helpful.
Other members will have advice, please consider these too.
This same thing is happening to mine. I was wondering if she was pecked or stung by something. Yours looks more obvious because of the dried blood. I can't tell if mine was pecked but she looks the same.