When I went out to collect the eggs I noticed one of my pullets (red sex-link) making an abnormal breathing sound, otherwise looks and acts normal.... It has been very cold out down in the single digits. I have a 3 other red sex-link pullets, a brown leghorn pullet, and a brown leghorn roo... all of them are in the same area together. Do I need to separate the one with the breathing problem? Should I bring her in the house? What could be wrong with her?? This is my first time raising chickens and also their first winter. What should I do??