Pullet with Yellow Nasal Discharge, no other symptoms

[Gingerweavers]

I wouldn't medicate them all. Just the one(s) that are showing any signs of illness.
Antibiotics will only treat any secondary infection(s). 

If she is eating, drinking, pooping and still active, then play it by ear. If she has something like Infectious Bronchitis or Mycoplasma, antibiotics may help clear up the mucous, but the virus/illness will have to run it's course.

Thank you so much for your advice. It is much appreciated!