Layer Hygiene & Management/Vaccination Handling & Titor Monitoring
Prevention of disease
This aspect of poultry management must receive constant, close attention. Failure to maintain a high standard will usually result in an unhealthy flock. The basis of poultry health management is:
- The isolation of the flock from disease causing organisms – quarantine.
- The destruction of as many harmful organisms as possible – hygiene.
- The use of an appropriate vaccination program – trigger the birds’ immune system.
- The use of appropriate preventive medication programs – for diseases for which there are no vaccines.
- The use of a suitable monitoring program – to monitor for the presence of disease organisms and the success or failure of the hygiene program or the vaccination program.
The principle need is to maintain control over the means of entry by disease causing organisms. These may enter by several routes:
- Poultry – introducing stock as day old chickens is considered to be the lowest risk method of restocking a poultry farm. Older birds are more likely to be diseased or at least carriers of disease, even if not showing signs.
- Wild birds/other animals – these often carry the causes of disease and are likely to fly or move from one poultry farm to another if the farms are close enough. The best way to prevent this is to ensure a suitable distance between farms and a minimum of 5 km is recommended. A security fence 2 metres high and with a controlled entry gate should surround the poultry farm and all sheds should be protected from entry by wild birds and all other animals by secure wire netting.
- Wind – insects and dust carried on the wind from infected to clean farms may also carry the causal organisms of infectious disease. The best way to prevent this is to ensure a suitable distance between farms and a minimum of 5 km is recommended. This distance is influenced by the direction of the prevailing wind. Insects and dust travel further with the wind than against it, and the presence or absence of barriers in the form of hills and high vegetation that catch the dust or insects.
- People and vehicles – the most common visitors, including vehicles, are very likely to be those that have had contact with other poultry whether they be chicken delivery vehicles, feed delivery vehicles, service people and their vehicles or neighbours in the same business. Entry should only be given to essential visitors and people and vehicles should enter only through a disinfectant wash facility and visitors through a shower/change facility. Disinfectant footbaths and a change of footwear prior to entry to each shed are also recommended. In some circumstances a shower and change of clothing should be required prior to entry to all poultry house. The organisation of staff around the farm is also of importance. Wherever possible, staff should be restricted to one location. However, in some situations there is a need for staff to move from one shed to another. In these cases the principle requirement is to do so in a way that carries the least risk. This means that the normal practice is to move from youngest to oldest flocks on the farm, leaving disease flocks, no matter their age till last.
- Used equipment – no used equipment should be allowed entry to a poultry farm. If it becomes necessary to allow such entry or to move equipment from one house to another, it should be thoroughly cleaned and disinfected prior to doing so.
- Food and water – when a diseased bird eats or drinks from a trough it will leave behind contaminated food or water. While it is difficult to prevent this within one pen, if possible, the choice of feeder and drinker may minimize or slow down the transfer of disease from one bird to another. Under no circumstances should open feeders and drinkers extend from one pen to another. All drinkers and feeders should be kept clean even if they have to be cleaned daily.
- Flies and rodents – in addition to the points raised in relation to distance from other flocks to minimize the movement of insects and animals from one farm to another, all fly and rodent populations should be controlled because they can carry disease causing organisms and pass them on to the stock.
The practice of good hygiene kills microorganisms, including those that cause disease, and all farms carry populations of microorganisms. Therefore, good hygiene practices are an important part of poultry health management. There is an overlapping in the use of the terms quarantine and hygiene.
Good hygiene practices include:
- The thorough cleaning of poultry houses and equipment after each flock has been removed.
- The use of vehicle disinfection and wash facilities.
- The use of foot baths at the entry to each house.
- The provision of footwear at the entry to each shed.
- The use of clean litter material after washing the shed and not re-using litter. Litter in the poultry house should be managed to maintain it in a dry friable state without caking or being too wet.
- Removing all dead birds daily and disposing them in a recommended manner.
- Maintaining all houses and ancillary buildings and surrounds in a clean and tidy state.
Vaccination is aimed at triggering the birds immune system to produce antibodies to fight infection. While not all diseases can be vaccinated against, all potential infectious disease threats should be identified and a suitable vaccination program developed to help combat those that can. Veterinary advice may be necessary to design a suitable vaccination program for each farm.
The keys to effective vaccination are:
- The potency of the vaccine used and/or its suitability for the disease strain to be controlled.
- The handling and storage procedures for the vaccine during travel and on the farm.
- The use of the recommended application techniques.
- The adherence to the recommended program.