Quarantine is important but there is some debate about for how long, what's best and the happy medium.
Most of the rules stem from the import/export of wild birds, not from, and please excuse the expression, the stock available. If this was California about (I think 4 years ago), strict quarantine would be necessary due to that outbreak of Newcastle's that occurred.
The 30-day full quarantine doesn't mean it isn't the best thing, but where the standard was set was when, at least in the US, things were different. It's still the most safest, hygenic, cleanest, worry-less, and all that...but it was also at a time when avian vets were not around and there were no standards, so a 'governmental' one was sort of set.
Today, it's not that hard and fast. It's in the books and it is advised, but if a vet gives the ok or an parront thinks it's ok... it's ok. In absence of an outbreak (like the Newcastle one a few years ago - which was limited), even the avian flu - which is affecting the poultry-type birds, the 30-day restriction can be cut and dry for some or a 'in the first 30 checklist' for others.
But the absolute is one that only a vet and ultimately a parront should do. Knowing where and how the rule occurred can really help to answer the individual situation.
The only thing I do know is do your best with what you have and don't look back.