I had a hatch of a dozen Orpingtons and 4 seramas together, no one was picked on because they hatched together. When they were about a week and a half old I purchased 5 more orpingtons of a different color and did not have another cage for them so I just put them with my chicks. The 5 new ones appeared healthy and I keep my chickens well maintained and healthy. A couple days after they got here I noticed the new chicks were sneezing but they were walking away from the water bowl so I didnt think anything major of it I assumed they just drank too fast or something. Well now about a week after that I see the entire pen is sneezing and there is a sound like fluid rattling in their chests! They are all active, eating and drinking more than ever, running around and playing, but I noticed the seramas are breathing really heavy I guess due to the fluid in their lungs. They are still under a heat lamp kept around 90 degrees and they are fully protected from drafts. This is not good! These babies are my entire flock! I bought all these hatching eggs from the best lines I could find and then the new orps were also of good lines! I dont know what to do, I tried culling, I did one chick and my assistant (sister) started screaming when I took its head off and so now I cant do the rest because she wont stop talking about how horrible I am for it. So my question is............ Can I treat them? If so, how? Will they still transmit the sickness to other birds?