Thanks for replying.I hope your tests come back with something more manageable, but meanwhile, and always, it's about practicing good biosecurity. All the birds you have are already exposed to whatever's going on, so your birds, chicks, and hatching eggs are not salable, and can't leave your farm.
If you don't already, your barn boots and clothes need to only be used on your farm, and not leave to go elsewhere.
If the tests come back positive for MG, I'm so sorry, and would be crying too, and seriously consider depopulating the flock. At least if it's MG, that will solve the problem, unlike Marek's disease, for example, which is present for a year or longer.
Also, if the tests come back inconclusive, have the state lab necropsy one of your sick birds, which will give a complete picture.
Again, I'm so sorry,
I'm so sorry!
Get necropsies done! Contact your state veterinary path lab directly, and get them there. Chilled, wrapped in plastic, and not frozen.