It's good that there's no worms there.
How long have you had these birds? Have you introduced any new birds lately?
We've had these birds since they were about 10 days old. We've introduced two chooks 3 weeks ago, and 2 weeks ago, these Dorkings (at 11 weeks old) were introduced to the entire flock (including the two new birds). The Dorkings are in a temporary pen inside the main pen, to get them use to each other before we join them together. One thing I can tell you, the main flock has had a cold on and off since the weather changed at the end of the heat/humidity. Most of the girls are fine now, but one isn't 100% yet. There's another who still sneezes on occasion too. I probably should have waited until everyone was 100% before putting the Dorkings into the same yard, but we did it because they're getting so big, and the temporary grower pen was just getting far too small for them. (Now I feel guilty!!)
It's quite normal for birds with a resp infection to both cough and shake their heads. Sometimes those with a lot of mucous will even fling it out of their mouth or nostrils by doing this. Have you had a look in the choana? That is a slit in the roof of the mouth. Sometimes food can get caught there.
I don't think we've seen the choana.. We will take a look, but I didn't see any food inside her mouth at all, except the bits around the beak.
Sorry about the croup thing. I forget that some people haven't had to deal with it. Croup is a condition that young children can get as a result of a viral infection of the upper airway. The throat can swell and they get a cough, wheezing and/or hoarse and laboured noisy breathing. It usually happens at night. The usual first aid is to get the child into moist air. Those without a vaporiser go to the bathroom with the child, close all doors and windows and run the shower on hot until the room steams up. Sometimes the breathing eases very quickly. I've found it can also work in some cases for asthmatics as dry cold air can be a problem for them. If it doesn't work then you get them to hospital for medications, but I've found the bathroom steamup very useful over the years.
Ah, no worries! Perhaps a long shower is in order.. (for me!!) and chooky can come into the bathroom with us. It's not exactly air-tight, though.. if it helps her, we'll do our best.
So, if it is a resp. infection or disease.. is there anything else we can do for her? Would it help if I had a short video of her symptoms?
Loving all things Dorking!