Just to follow up on this:
After sneezing for about 3 weeks I gave her poly vi sol (without iron) in her water and in 3 days she kicked the cough completely. I'm not entirely sure of the implications of this but anyway that is what worked.
This has been going on for 5 days now. That seems like too long for her to sneeze it out or for the problem to take care of itself.
I did take the pine shavings out of the brooder for 24 hours, that did not make a difference. Any ideas?
I have 20 young chicks, 19 are 14 days old and 1 is 12 days old. I had initially used a bedding of cardboard covered with newspapers covered with paper towels for traction, changed daily. Yesterday I switched to pine shavings. Within two hours the 12 day old chick (Araucana) started sneezing and...