b) har oprindelse i en flok, der mindst fjorten dage inden forsendelsen eller indsamlingen af rugeaeg ved stikproeve af kloaksvaberproever fra mindst 60 dyr i hver af de beroerte flokke har vaeret underkastet en virusisolationsproeve for Newcastle disease foretaget af et officielt laboratorium, uden at der er fundet aviaer paramyxovirus med et intracerebralt patogenicitetsindeks (ICPI) paa over 0,4 og
(b) originate from a flock which has undergone, no earlier than 14 days preceding consignment or collecting of hatching eggs, on the basis of a random sample of cloacal swabs of at least 60 birds of each flock concerned, a virus isolation test for Newcastle disease, carried out in an official laboratory, in which no avian paramyxoviruses with an Intracerebral Pathogenicity Index (ICPI) of more than 0,4 have been found; and