1. Animal Science Unit, Institute for Agricultural, Fisheries and Food Research, Melle, Belgium
2. Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
3. Galluvet, Lummen, Belgium
4. Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
5. Experimental Poultry Centre, Geel, Belgium