First of all, you made a good call to put them all on an antibiotic when you saw signs of respiratory infection. Chances are good you caught it before it went too far and they will probably all recover, albeit not all at the same rate. Be patient and just keep an eye on them before you think about trying anything else.
Back to the Polish. Over the years I've been keeping chickens, I've learned that they will scratch at any body part that is causing them discomfort, whether it be pain or itching. So the Polish is having issues of discomfort in her eye region. I would check her very carefully, looking for swelling, and ingrown feathers. Chickens that have "decorative" feather features, head crests, foot feathers and such, may get an emerging pin feather once in a while that makes a "U" turn and grows back in on itself.
You'll notice swelling around a pin feather first, then you may see the "U"turn. Sometimes all it takes to correct it is to take a tweezers and gently pull on the emerging shaft until it comes back out. If that doesn't work, then you can free it by taking a razor blade or small scalpel and making a tiny cut over the ingrown feather. If you do that, put an antiseptic on it.
If the Polish has swelling around the eyes and face, however, it could be a sinus infection. This is not uncommon, especially if several of the chickens have shown signs of respiratory infection. Getting a steroid eye drop solution from a vet or feed store will solve that problem. I've had cataract surgery so I have a supply of leftover antibiotic drops and steroid drops, so if you can't locate anywhere to buy these, ask your older relatives and friends who've had cataracts removed if they still have any of these drops left over.
Hopefully this additional information will help you figure out what's causing your Polish discomfort.