You could try your State Veterinarian through your Dept. of Agriculture. I believe the USDA also has a free disease-testing service. To find out more, call 1-866-536-7593,
Here's what the Merck Vet Manual says:
"Because early treatment is important, water medication is recommended immediately until medicated feed is available. Erythromycin and oxytetracycline are usually beneficial. Several new-generation antibiotics (eg, fluoroquinolones, macrolides) are active...