eye infection?

We brought a new group of hens home 5 days ago.  This morning one hen had "stuff" in one of her eyes.  It looked white & foamy, like a spit-bug nest in the corner of her eye.  We cleaned it out & she has been acting normal but the eye is certainly not normal.  No one else has any symptoms.

She is an Americana hen, not sure of the age but she is mature and laying.  She seems in good weight and otherwise healthy.

Besides isolating her & rinsing the eye occasionally, what should I do and how worried about the other chickens should I be?  Very new chicken mom.

no sneezing or wheezing and her other eye looks fine.
 

Eye looks better this morning, no more bubbly stuff.  Some left over crusties, but can see almost all of her eye.  Breathing still normal, alert and scratching around.  She is in chicken solitary, I've been rinsing her eye with a warm boric acid solution followed with a swipe of triple antibiotic ointment.  Started her on Terra-vet 10 in her water (1 tsp/gallon).

Should I dose the rest of her flock with the terra-vet as a precaution, or wait to see if anyone else develops issues?
 

The hen's eye cleared up, so the third morning of looking normal we put her back in with her flock.  Within 2 hours the opposite eye had bubbles.  So she is back in chicken isolation and having the other eye flushed.  Everything I'm reading says bubbles are respiratory / sinus, but  I think it is very odd that it could be "fine" for days then switch eyes immediately after being put back in the pen.  Thankfully every one else still looks good.