buying a dog from the US to bring to the EU/Poland+Germany

Question
Dear Experts,
we are looking into buying a Labradoodle (low-allergy) puppy from a breeder in the US to bring to Europe (Poland). We would pick up the puppy from the airport in Amsterdam and drive it into Poland by car. What minimum age would the puppy have to have upon entry to the EU, are there any differences in the laws of the countries we would be crossing (Netherlands, Germany, Poland) or do they all follow the same EU regulations, and what additional legal aspects are there to be considered when acquiring a dog abroad to bring to Poland? We would like to make sure that we don't run into any legal problems with all those international borders and rules, all the more seeing that we are not Polish nationals. Is our own nationality relevant in any way?
Thank you very much in advance for your time and effort,
sincerely,
Anna.

Answer
Anna,
You are wise to be thinking of all these questions.
First off, you'll need a Pet Passport:
from Wikipedia...
The Pet Travel Scheme ("PETS") is a system which allows animals to travel easily between member countries without undergoing quarantine. A Pet Passport is a document that officially records information related to a specific animal, as part of that procedure. The effect is to drastically speed up and simplify travel with and transport of animals between member countries, compared to previous procedures, if the regulations are followed. Pets can only travel through Animal Reception Centres that are currently licensed with DEFRA.

One example is the Anglo European company, based at Robin Hood Airport, Doncaster Sheffield.

PETS was originally introduced for the benefit of animals entering or returning to the United Kingdom from other European Union countries, since historically the UK had very strong controls to safeguard against rabies including a compulsory 6 month quarantine period on imports of many animals. On October 1, 2001, several European Union countries introduced the PETS scheme, under which animals from any member country may freely travel (with the correct procedure) to any other member country on approved carriers. Over time the scheme has rolled out to other countries such as the United States, Canada, Australia and New Zealand.
end of Wikipedia

Unfortunately, Poland isn't part of the Pet Passport system, at this time.  So, you will need to find out from Poland what the entry requirements are.  Here is the website where I found a bit of info re: entry of dogs into Poland:  http://www.washington.polemb.net/index.php?document=94

And here is the direct page for the entry docs of dogs coming into Poland:
http://www.washington.polemb.net/files/psykoty.pdf

You will need the Pet Passport for your puppy to enter Germany and the Netherlands without quarantine, and the above mentioned paperwork for your puppy to enter Poland.  The minimum age is old enough to have completed the steps to have the Pet Passport vaccinations and chipping completed.  
Good luck.