Chickens dying overnight month apart

[Bryverine]

Private veterinary practices are expensive and not very knowledgeable about poultry so they are not the best option for a necropsy and most will probably send the carcass off to the state facility anyway and charge a significant fee on top of the necropsy fee for handling.
Depending upon your location in the world, state agricultural or veterinary diagnostics labs are usually subsidised to a greater or lesser extent. Some charge as little as $20 (California) others can be up to $100. Some will charge extra for additional testing, others do not. They should clear any additional charges with you before proceeding to incur them. If you let us know where you live we can try to find the website for the appropriate lab and advise on charges. Carcasses need to be refrigerated (not frozen) and usually delivered in person or posted in an insulated box over ice.

I live in Albuquerque, new mexico. Thank you!