108. A disease challenge may be first noticed by a change in water consumption or a reluctance to eat. It is, therefore, good management practice to keep daily records of feed and water intake. If a disease problem is suspected, a veterinary surgeon should be consulted. Early, appropriate treatment of a disease incident will minimise the adverse effects on the birds' welfare, health and reproductive performance and also minimise the effects on the welfare, health and quality of the progeny.
109. Breeding birds tend to have very few health problems and are given a comprehensive vaccination programme both to protect their own health and pass on immunity to their progeny. It is universal practice to vaccinate breeders for coccidiosis, Mareks disease, Newcastle disease, infectious bronchitis, infectious bursal disease and infectious avian encephalomyelitis (epidemic tremor). In addition, depending on location, vaccination for salmonella enteritidis, avian rhinotracheitis, egg drop syndrome, chick anaemia and reovirus may be required.
110. The commercial availability of an effective coccidiosis vaccine in the last 10 years has removed the principal cause of mortality, uneven growth and poor welfare in young breeding birds, which generally have good health status and low mortality. It is now quite reasonable to expect birds to be reared to 18 weeks with no more than 2% losses, either culls or mortality.
111. When birds are transferred to their laying quarters at about 18 weeks they receive treatment to prevent the development of Ascaris worms and are vaccinated by injection to give long lasting immunity to various infectious diseases. An example vaccination programme is at Appendix C.
112. The vaccination programme will control all the major infectious diseases, so that mortality is generally due to a variety of miscellaneous conditions. These include peritonitis, heart failure, tumours, joint infections and injuries.
113. The improved health status of the national flock is also due to better preventive health management. Generally referred to as "bio-security", most breeding farms have strict rules on access by visitors, the use of protective clothing and cleansing and disinfection of equipment and transport. During lay, especially in summer, it may be necessary to treat the equipment in the houses to remove parasites such as red mite. This parasite is becoming more common and the use of automatic egg collection systems with slats makes control more difficult.
114. Each flock should have a written health and welfare programme produced, where necessary, with expert advice. This should set out health and husbandry activities covering the whole of the production cycle. The programme should be reviewed and updated annually by the farm manager and should be available for inspection by enforcement authorities.
115. Infectious diseases should be controlled by good management and attention to detail including the keeping of daily records of feed and water consumption.
116. Immediate veterinary attention should be sought at an early stage in any outbreak of disease so that the cause can be determined and appropriate action taken.
117. Diseases caused by external parasites should be controlled by appropriate parasiticides.