Backyard Fowl Keepers

This sounds like a mild case of eye irritation, possibly from dust, bedding, or a minor infection. Since none of the other chicks are affected, it may be individual sensitivity rather than something contagious. Keeping her eyes clean with a sterile saline solution is a good first step. If the issue persists or worsens,especially if you notice swelling, discharge, or lethargy,it might be worth considering an antibiotic ointment like Terramycin. Otherwise, ensuring the brooder is well-ventilated and clean may help prevent further irritation.

It could be mild conjunctivitis. I'd keep treating it with warm saline and keep an eye out for worsening symptoms. If no improvement in a few days, antibiotics may be needed.

A warm compress is a great short-term fix, but if her eyes are sealing shut daily, I'd be concerned about a possible bacterial infection or early respiratory issue. Look for other signs like labored breathing, nasal discharge, or lethargy. If it's just eye irritation, keeping her brooder extra clean and dust-free while monitoring for changes should help.

Some chicks are just more sensitive! If she's otherwise acting fine, I'd just monitor her and continue cleaning her eyes until she grows out of it.