sneezing, wheezing chicks

I also have this posted under emergencies, but no one has been able to help, so here it goes. I have 29 week old silkie chicks. After about 3 days one of the smaller chicks started shaking its head and making a loud squeak, kind of like it is trying to clear its nose. Today this chick is squeaking every time it breathes, even when it is sleeping, kind of sounds like a cheap squeaky toy. After posting this on BYC, I went back to look at him and I saw two more of my chicks shaking their heads like they are trying to get something out of their nose. They are doing this about every 30 seconds. I have now put these three into one box hoping this is just something they are going through, I am scared for the rest of my chicks. They have no other symptoms, they are eating and drinking and up and about. Also the one that has had this the longest was opening its mouth to breathe earlier. Seems to go through spurts of this opening his mouth thing. Has anyone ever heard of anything like this??