There are molds and there are molds...so many different kinds fit under that genre.
Many are beneficial, some are toxic...most folks can't tell the difference.
They can be a respiratory irritant, chronically or not.
An antibiotic won't do squat against them and may well compromise the 'natural' immune system enough for other organisms to bloom to the point of unhealthfulness.
Decades old pet peeve of mine to misapply and/or overuse antibiotics...in people or animals(pets and livestock).
Balance of good foods and environment will keep the healthy healthy...the sickly won't survive, as it should be.
My birds regularly have little 'sneezing attacks'...usually after eating or drinking too fast or while dust bathing.
Only had one bird with some kind of respiratory problem, swollen sinus, gunky eye, sneezing.....
...was still fairly active so I didn't treat, she got over it within a week or so. Had slight re-occurance, but she recovered fully.
She's gone now, was an older bird, culled for soup, that I got as an adult as my starter flock.
Might she still have been carrying it, maybe...might the whole flock be carrying it, maybe...but everyone seems healthy so....<shrug>
Early morning ponderings...just another perspective.