Where can I get testing for respiratory diseases in Florida Panhandle?

I have a flock of 3 3 1/2 month old pullets, all raised together, and were very healthy. Well, a few weeks ago, I decided (bad decision) to order 2 Silkie pullets from an NPIP certified breeder. They came through express mail one week ago as of yesterday. Before even taking them out of the shipping box, I saw that one had crust around it's nostrils and was sneezing, a few minutes later, noticed that the other also was sneezing. From there, they went straight to quarantine in my garage, my other chickens are in a coop in the backyard. The same night, when I was getting the new ones cleaned up after their journey, I heard a significant gurgling sound from both of them, then came a lot of sneezing. I researched, and decided that they needed to be checked by a vet. The vet told me that by the symptoms, it was likely Infectious Coryza or Mycoplasma. Gave me 10 day antibiotics, and told me to return the chickens to the breeder as soon as I felt comfortable shipping them back, so that they would not infect my flock. Well.... Tuesday evening, 5 days after they arrived, all 3 of my "healthy" flock start sneezing. I have maybe even seen trace amounts (or could by my overactive imagination) of clear mucus in the nostrils. But I have definitely noticed a frequent chewing/almost swallowing thing that they have been doing, just like the really sick new chicken does. Probably clearing mucus I imagine. Also, the day after getting the birds, I informed the breeder, and she was really surprised, BUT, proceeded to tell me how many of her birds have been fighting COLDS lately. Working in the medical field, and previously working in animal hospitals, I wanted to freaking scream! A cold is contagious! And in avians, a "cold" might as well be Tuberculosis! So, now I am paranoid that my previous ones are sick, and my heart has practically sank into my stomach, as they have grown to be my pets. Also, this has crushed my hopes of having a few more birds, since I doubt I can ever add any unless mine are culled ( which I don't know how I feel about) Anyways, to the point, where in the Florida Panhandle can my birds get tested for respiratory diseases? I am aware that my vet can test for Mycoplasma for $130, but there is the cost, and it's just to test the one thing. If anyone can help me with resources I would be incredibly thankful.