Yes, there are inspection regulations for pet stores. Unfortunately, the organizations that enforce them are grotesquely underfunded and understaffed. It's all they can do to handle the worst mass-offenders, let alone a store whose worst crime is a handful of sick cockatiels.

As for incubation periods, that would depend on me being able to confirm the exact disease responsible. There are a *lot* of things that can cause the same signs in birds, and almost all of them are nearly impossible to diagnose. (Birds are notoriously difficult to catch definitive diagnoses for - any given test is about 50% accurate. It sucks, and we're working on new tests, but that's all we have right now). I've been sending the bodies out for testing, but all the tests have come back inconclusive, so I don't have a leg to stand on against the store. It would be great if the owners decided to sue, but I can't bring it up or encourage them, and if they did I really can't safely testify on their behalf.

I've investigated this as much as I can, trying to find a safe way to help get this under control - but it seems like all I can do is hold people's hands while I tell them their new pet is sick, tell them it's not their fault, and make sure they don't make the same mistake twice. Damnit.