Any vet in the US is not going to give you much information. Your best bet is to start the chicks on Corid for now and then do an online search to get it ordered.
There are a couple of articles here on BYC to read up on, perhaps a link or two also. Mine comes from Jordan but is ordered from...
Yeah, not gonna happen, it is not approved in the US and has to be ordered from without. Canada, Jordan, and Australia are a few of the source countries.