It's already started here too -- fireworks!
I live next to an orchard and they use an air cannon at times to ward off flocks of birds. My adults are fairly used to the boom and don't pay it much attention. (I think that flocks of birds would get used to it as well - wander at the effectiveness of this noise

).
The other night, I think their timer was out of whack - the thing went off about every 10mins for a couple of hours. I looked on my cams - the adults had tucked heads and appeared to be sleeping fine. Youngsters in other pen were wide awake. This was with fans running, which does make some noise. Youngsters lounged and took quite a few naps the next day, but seemed o.k., but I kept close watch on them.
Noises do bother my dog as well, he is losing his hearing, so he doesn't get quite so anxious with the booms and noise from fireworks. He's a sky watcher though, so if he sees dark clouds or it's sprinkling rain - he associates that with thunder/lightning - then his anxiety level goes up.
I have used Bach Rescue Remedy in the past for the dog when he was younger and more prone to severe anxiety. It worked fairly well - there are different formulas for pets and people - may be worth exploring.
For really stressed birds use Poultry Nutri-Drench - this is quick uptake. Worth a try and would do no harm.
Just my thoughts

I hope everyone has a safe 4th.
Bach Flower remedies can be found online or if you have a Co-Op (organic/natural) store - most of the time they carry it too.
http://www.bachflower.com/rescue-remedy-information/