Well, I don't know anything about chicken to human diseases other than the bird flu. But from personal experience I will tell you this: If you are using pine shavings (yes, just pine, white pine or any other conifer type shavings) in your brooder, it can make you sick if your area is not well ventilated.
What happened to me is that I was having intense stomach pain, right in the middle, right below my sternum (think liver). So I went to the E.R. complaining of this awful intense pain, and they didn't have a clue what it was! They did alot of testing and drew blood and couldn't come up with anything EXCEPT that my liver enzyme levels were WAY off. They tried to figure out the cause and couldn't determine it.
A few weeks later I was surfing a webpage (the house rabbit society) and came across an article that said liver disease, so I clicked on it. It described how pine shavings give off a chemical called phenols and that it was making peoples bunnies die from liver disease. Well, as a rabbit breeder, using the thick bedding instead of wire cage bottoms method, I had literally pine shavings everywhere in my small house. So I put two and two together and took three rabbits to the vet. Two rabbits of different ages from inside the house and one "control" rabbit from out doors who had never been in the house. The two from in the house came back with HIGHLY elevated liver enzyme levels and the outdoor rabbit was completely normal. HMMM, I said!
So we changed out the bedding in the cages, took the bunnies back to the doc and low and behold, the same exact three bunnies, tested normal. I went back to the doctor with my findings and they re-tested me. Liver enzyme levels returned to completely normal within a couple of months.
So if you're using pine shavings, I'd reccommend changing it out for paper pulp or something else. Or, remove them from that room and make sure the room they go into is ~extremely~ well ventilated. The phenols will build up in your system, making progressively worse symptoms. It also takes a little while for the enzymes to return to normal.
I don't know if this is your current problem or not, but hopefully it helps someone somewhere, because now that I have felt the pain, I will never do that again!
Who knew that a hobby could be potentially lethal?!?!?