around 5 week old chick with breathing issues?

[liito]

i recently got three five-week-old chicks, and one of them is displaying signs of respiratory disease, but i’m not sure.
she keeps closing her eyes and is very lethargic, she keeps sneezing and at times had open-mouthed breathing. we can’t get her to a vet yet because we are very busy. she’s only been having these symptoms for about two or three days now, and none of the other chicks have any signs.
she sneezes very hard and sometimes just falls asleep in our hands very quickly, something none of the others do.
she’s been eating and drinking fine, we’ve been administering treatment for coccidiosis through her water for around a week now.
her poop looks normal, but we are really unsure.
i would really appreciate some advice as to what to do until we can get her to a vet. she’s currently in a well-heated, ventilated cage which has raised them well so far.

 

[nchls school]

Many chicken ailments are contagious to other chickens. Consider separating the sick bird until you know what is wrong. Raw and unfiltered apple cider vinegar may help. 2 tablespoons mixed with a gallon of water used as the chick's drinking water. Give it to the other chicks as well.