Quantification of rHVT-F genome load in feather follicles by specific real-time qPCR as an indicator of NDV-specific humoral immunity induced by day-old vaccination in SPF chickens., Rauw, Fabienne, Van Borm Steven, Welby S, Ngabirano E, Gardin Y, Palya V, and Lambrecht Bénédicte , Avian Pathol, 2015, Volume 44, Issue 3, p.154-61, (2015)