Poultry production / Farm Types / Housing Types / Grand parent stock

Grand parent stock

Food safety and animal health Risk Factors at GPS farms:

Farm location and equipment
The choice of a suitably isolated geographical location, taking into account the direction of the prevailing winds
The area immediately surrounding the poultry houses should be free from vegetation and debris and ideally this should consist of an area of concrete or other similar material. An exception to this would be trees for heat control, with the exception of fruit trees which could be attractive to birds.

Totally enclosed houses provide greater control over the birds' environment.
Ventilation systems can disperse contaminated particles through the whole stable.

Hygiene / Pests Control

These farms are at the top of both the meat and egg production columns. Therefore there is an urgent need for good hygiene practice. Point out the risks of many visitors from outside the farm

Hygiene barriers including showers and company clothes are urgently recommended.

Visitors should preferably not have been at another farm at the same day. Appropriate disease security precautions should be pointed out. This could include showering and changing facilities (hygiene barriers) adopted for all visitors to the establishment and for all staff entering individual poultry houses

Control of all types of vermin such as rats, mice, insects and wild birds should be carried out consequently and frequently.

Long lasting rounds

GPS farms normally have relatively long production cycles, sometimes over 1 year. This means that build up of dust and manure may be the basis of neglecting hygiene and attention. Frequent checks by external experts may help stay alert. All in all out systems are preferred, but at larger farms long production cycles may also lead to replacement of parts of the population. This is also the case when cocks are replaced in within flocks. Here extreme hygienic awareness is needed.


Feed for GPS, PS and Layers often is not pasteurized by pelleting. Especially the Salmonella control may become endangered, so alternatives should be preferably be applied. These alternatives are adding short chain or medium chain organic acids to the feed or strictly use Salmonella free raw materials.

 Feed silos should be cleaned  regularly, because of mould growth at the roof area. Poor storage of the feed: closure of silo’s, dirty silo’s, bad hygiene at storage places, rodents, birds, bad humidity and temperature etc. 

In case of Salmonella infection, the silos should additionally be disinfected.


Water supply systems at a farm can take the water from either public supply systems or private wells. The first system is normally safe for use as long as the farm infrastructure allows close system until at animal level. Private wells should be checked for their water quality at least 2 times per year including microbiological and chemical properties.

Closed nipple systems normally are less polluted than open drinkers. On the other hand open systems can easier be cleaned during the production rounds. Moreover when medication is applied through drinking water, nipple systems should be monitored closely for adverse effects like slime formation inside the tubes.


 Free run and free range housing systems have to deal with bedding material e.g. straw or wood shavings. During the production cycles monitoring of the quality of the bedding should be part of the managing practice. Wet spots should be avoided and removed, but too dry conditions may lead to a very dusty environment for the animals.

 Farm system

 Roughly three farm systems are used for GPS: Cages are used for individual housing of hens and cocks, free run or deep litter where both hens and cocks are running freely on the floor and on slatted floor, and free range where animals have additionally access to the outside world.

Ground eggs have to be removed frequently and kept separate from the rest. Washing or cleaning of these eggs should be avoided since contamination of contents may occur. During hatching process these eggs can cause undesired contamination of brooders or hatchers.

 Nests should be checked frequently for presence of cover materials and damaged eggs. Egg conveyer belt are occasionally used in larger GPS farms. Every stable should have its own equipment, which should be well maintained and cleaned frequently. Equipment for vaccination often is used for every flock which requires very strict hygiene.

 Trays for eggs should be either cleaned and disinfected plastic or new one way pulp trays. Lorries for transportation should be clean and bacteriologically safe.  When large hatchery trays are used they should be disinfected.

  Other farm animals

  Smaller GPS farms often have other animals such as pigs and cattle on site. Strict separation of species is needed, as is separation of equipment and people’s clothing. A certain logistic scheme can be of help: look after the GPS stock first, followed by the other species.

  Veterinary support

  Since GPS stock is very delicate, animal health is a very important issue. Vaccinations should preferably be carried out under veterinary control.


Stocking and drying of manure

 When manure is dried at the farm, cross contamination through dust can easily happen. The best alternative is separate the manure stock from the stables, and keep out pest animals.


 Stressors such as replacement of cocks, climate conditions, vaccination or molting should be avoided or kept in focus. In cage housing systems artificial insemination takes place, which may cause stress in both genders. Beak trimming and vaccination cannot be done without handling the animals.

Service teams

Beak trimming and vaccination often is carried out by so called specialized external service teams. These sometimes go from one farm to the next. They should be aware of cross contamination and strictly obey hygiene rules.

 Egg storage and transport

Eggs should be stored under required climatic conditions, both for preventing spoilage or growth of fungi, but also for keeping up the hatch conditions.

Trays for loading eggs have to be either clean plastic ones or one way (new) pulp trays. Transport vehicles should be clean and preferably not collect eggs at different farms without external disinfection of wheels. The better way would be a loading area, apart from animal facilities.