Do you have some Tylosin or Amoxicillin or Enrofloxacin on hand?She’s between like 1.5-2 weeks. I’m assuming I would need to order antibiotics?
If not you could use this online shop
https://jedds.com/collections/poultry-treatments-respiratory
And until delivery you can brew some tea with thyme, oregano and fennel as natural antibiotics.
Give lukewarm instead of water, prepare fresh daily. All the other chicks can drink it as well.