Some are bothered, some aren't, depends on the breed, our big orps just zone-out and sleep through the whole thing, while my friend who keeps other lighter more skitish breeds say hers are terrified and go right off laying eggs!
If you can bring them into cages indoors then that would work, if not, just try and insulate the hen houses with carpet etc. we have a good friendly community around us thankfully, and most folks will come round and tell us when they are having fireworks, so it gives us chance to prepare, but like i said, our birds just sleep through with no problems. It's not the birds i worry about, it's my cats! :roll:
JubesXX