A survey of "normal" broiler mortality in East Anglia

A survey of routine mortality was carried out on six different broiler sites. A total of 535 individual post mortem examinations was carried out. The chief cause of mortality on all six sites was colisepticaemia. Fatty liver and kidney syndrome caused significant loss on three of the six sites and on three of them a low incidence of an oedema syndrome was of interest. Salmonella senftenberg was isolated during the first four weeks from the intestines of chickens from five of the six sites but on none of them was this occurrence associated with any manifestations of disease. The vaccination procedures against Newcastle disease and infectious bronchitis were not producing adequate immunity against a possible challenge by a virulent virus of either although the administration of the vaccines appeared to be causing stress sufficiently severe to be one of the factors predisposing to a high incidence of colisepticaemia.