Yes, that's what we're discussing. They only test (by taking blood from a vein in the underside of the wing) for Pullorum and Typhoid. These are only two of the very many diseases chickens can be carrying, without showing any symptoms.
You should definitely quarantine any chicken that you bring home, no matter from whom or where you purchase it. Always.
You should definitely quarantine any chicken that you bring home, no matter from whom or where you purchase it. Always.