australorps and dull combs

Well, the combs do get pale and a little shrunken when the hens are not laying, which, depending on where you are and the conditions they're in,, they probably won't be laying much in the winter time, if at all. And some hens combs get paler and more shrunken than others. It can also be a symptom of illness, though.
It's hard to say, because they can also act a little spacy and look a little dull if it is cold out. Are there ANY other symptoms? Are they eating ok? Drinking? Hiding? You mentioned acting timid, this might be a sign of illness, but again it's hard to say. Any discharge, coughing, sneezing, swollen eyes, diarhea, abnormal droppings? Did you get the chickens altogether or did you add the Australorps or the Leghorns to the flock separately?
You could start with some organic Apple Cider vinegar, only get the organic kind with the mother in it. One tbsp per gallon in drinking water. It's a good natural antibiotic and preventative. I would watch them for a few days and see what develops. Watch carefully though, because if they get worse or start showing other symptoms, then you need to move quickly in treating them. They will not show symptoms, or will try not to, until they are quite ill, and they will not show symptoms if you are staring at them, so be aware of that as well.