what bedding are you using?
has the coop been cleaned recently?
dusts from dander or feed, built up ammonia, molds and mildews..
dusts in general can cause wheezing..
here's some info:
http://www.shagbarkbantams.com/oxine.htm
describe the droppings..color and consistency.
other symptoms of respiratory illness include:
lack of appetite, huddled, acting ill
swollen eyes, wattles or head.
drainage from eyes or beak..
mucus.
the bird doesn't have to have all these symptoms to have respiratory illness.
if you suspect respiratory illness..try and get some Tylan 50 injectable and syringes at most farm/feed stores.
other meds: erythromycin (sometimes called gallimycin or Ery-mycin), LS-50..
there is also a water soluble powder Tylan available.