Please help! My chicken has been sick!

[SweetTea&Chicks]

Lately my chicken has been acting sick. She’s slow, won’t go with the other chickens, and now she’s laying down and closing her eyes. She’s about one year old now and I’m pretty sure she’s a Red Sex Link. She has no signs of an injury or trauma. I discovered yesterday that the chickens had lice so I treated them with Permethrin 10. She eats her feed and drinks fine and will only peck around a little bit at the grass. All of the poop in the coop looks fine but there is some that looks runny. She can stand and walk fine. Sometimes she’ll make a purr sound when she lays down. So far I’ve put apple cider vinegar in the water and she drank a good bit of it. If anyone could help please do

 

[azygous]

You've mustered the first step in treating a sick hen and that's identifying that she doesn't feel well. Next you need to make a thorough examination.

-Has she laid any abnormal eggs? (Two in one day, or thin-shelled or shell-less)
-Have you checked her crop? (Is it empty, lumpy and hard, soft and squishy)
-Is her abdomen between her legs swollen?
-Is there any yellowish discharge from her vent? (White mucous tinged with yellow or blood)
-Have you examined her legs and feet? (Scales flush or lifted up, any crusty build-up, or swelling and black scabs on the bottoms of her feet)
-Any discharge from her nares or bubbling in her eyes, swelling around eyes)
-Look her over under all the feathers for any injuries and red, swollen skin that might indicated infection.
-Poop. Any signs of blood or worms?

Maybe there are some clues to be discovered after this exam.