Learn about Marek's disease. Get your chicks vaccinated if you can. The Merck Veterinary Manual says that almost every flock is presumed to be infected (see below).
If I remember correctly, vaccinations have to be done in the egg or on day one after they hatch. If Marek's shows up, do not despair. You can raise crossbreeds that will, in a couple of years, be resistant. I did it. You have to have the will to humanely put down a sick bird, or have your avian vet do it. My birds are a mix of chickens that were originally bred on just about every continent and country. I wanted them to have every gene I could get them. Fortunately I received a mix of 43 purebreds of many sorts from a rescue I took in and let everyone breed together. The third year of this, I had only one sick bird. Essentially, I bred my own landrace.
Sir Crows a Lot - I did CPR on a hen just a couple months ago. It can work. It didn't on my poor Elizabeth, but she was very old.
I use that wiggly plastic roofing for poop boards. Works great and I can cut it with heavy shears if I need to., plus, it's light weight. Don't use fiberglass panels. They break.
[COLOR=0000FF]http://www.merckvetmanual.com/mvm/poultry/neoplasms/mareks_disease_in_poultry.html [/COLOR]
Every flock, except for those maintained under strict pathogen-free conditions, is presumed to be infected.