If you are in the US, most states have a poultry lab. I will attach a link to a list below. You can call which ever is nearest to you and find out what any costs are and what kind of delivery options there are (some if you are close enough will let you drop off rather than have to ship). The call cost nothing, and at least you will have the info for the future, if needed. In some states the cost is pretty low, and the state ones are usually less expensive than having a vet do it.
https://www.metzerfarms.com/poultry-labs.html
https://www.metzerfarms.com/poultry-labs.html