Main Problems Rearing, diseases and vaccination Fowl pox: Very few cases were reported in mixed farms. Clostridial enteritis: Caused sudden death in more than 30% of young chicks. Zinc bacitracin in diet was used successfully as preventive treatment. In 2 farms all disease problems in breeders disappeared when good nutrition and biosecurity program were used. In one farm aspergillosis caused problems (respiratory problems in breeders and low hatchability) due to low quality hay in diet.