Infectious Bronchitis-does this sound right?

[WisconsinChickenWhisperer]

I got some new chickens to add to my flock. Quarrantiend (sp) them, they all seemed to be healthy, no symptoms of anything. I added them to my flock 5 days ago. Now, I have hens that are wheezing, sneezing, and coughing. It started with 2 hens this morning, now appears to be 2 more tonight. They sound terrible! I do not see any discharge from the nostrils or mouth, eyes look fine, wattles and combs look normal. They appear to be eating and drinking normally. Egg production has been off for the last couple of weeks, though. Could it be that the new hens are carriers of something, or do you think my flock was starting to come down with something and the stress from introducing new flock members just brought on symptoms?

The only other thing that I have done differently is I started sprinkling food grade diatomaceous earth on the bedding in the coop and started raking it in-maybe too much dust?

I am worried about my girls-any thoughts would help!

Edit: 3 days ago I did add some new scratch feed to their diet as well. It's a brand that I don't normally purchase, just thought that maybe they would like something a little different.

 

[WisconsinChickenWhisperer]

Went to let the girls out this morning, and I think I was mistaken about the other 2 hens being sick. It was pretty humid last night, so I am thinking that maybe the 2 that I thought were getting sick were just panting because it was warm in the coop. Still, other than the wheezing and occassional cough from the 2, everything else is normal. Everyone ran out of the coop this morning, everyone is scratching around, rooster is crowing. No listlessness, nobody acting as if they are "sick". I'm kind of at a loss, here.........