On the different kinds of poultry farms (e.g. broiler farms, layer farms, rearing farm, etc.) risks with regard to food safety and animal health do occur in the following aspects: Hygiene on the farm; Storage of compound feed; Feed and water systems outside and inside the houses etc.
In this chapter, these factors are discussed in more detail.
Many farmers are certified by quality systems which means that the farmer complies the rules of those quality system. They purchase compound feed from certified feed manufactures, apply good hygiene, keep record of events and materials, etc.
The hygiene standard at a farm is by far the most important condition for good animal health and for production of safe food. Of course there are other factors that play a significant role and in general a combination of factors (so called 'hurdles') do stimulate and enlarge the effects.
In the diagram the effect of regular Cleaning and Disinfection (C&D) is shown.
The red dotted line represents the situation where C&D is not regularly performed. The hygiene level is relatively low and there is a wide variation between before and after C&D. When the frequency of C&D is increased both the hygiene level increases and the variation is smaller, which means that the differences between before and after C&D is less.
Food safety and animal health Risk Factors at poultry farms:
Hygiene / Pests Control
Grand Parent Stock (GPS) farms are near the top of both the meat and egg production columns. Therefore there is an urgent need for good hygiene practice. Hygiene barriers including showers and company clothes are highly recommended. Visitors should preferably not have been at another poultry farm at the same day. These rules are also valid for Breeder Stock (BS), since here hatching eggs are produced. This of course does not mean that at Egg production or broiler farms, hygiene should be neglected. Hygiene barriers and changing clothes and foot ware should be generally applied.
PS and layer house normally have natural ventilation, which opens the possibility of introducing insects and other pest animals. Control of rats and mice should be of high standard, and wild birds should not be allowed inside the houses.
Control of all types of vermin such as rats, mice, insects and wild birds should be carried out consequently and frequently at all farm types.
Long lasting rounds or "all in-all out"
GPS, PS and egg production 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.
Organic farms are often small scale operations, so the need for presence of more ages or more flocks on site is more common than in traditional poultry farming.
At commercial broiler farms “all in- all out” production system is common. However during the production cycle sometimes flocks are thinned ones or twice. Thinning means that part of the flock is going to the slaughter plant one or two week before the final depopulation. During thinning crates or containers are entering the house, as is the loading crew. This operation exposes the remaining chicks to possible contamination. Therefore the farmer has to pay extra attention to the hygiene of people and equipment entering the house.
" All in – all out" systems creates the possibility to remove litter from the farm at once, so contamination of successive flocks by remaining litter should be impossible.
Feed for GPS, PS and Layers often is not pasteurized by pelletizing. 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 strict use of Salmonella free raw materials.
Transport of diets to more than one farm on one day includes the danger of cross contamination between farms.
Poor storage of the purchased diets: not well closed silo’s, dirty silo’s, bad hygiene storage places, rodents, birds, bad humidity and temperature etc. Feed silos should be cleaned regularly, because of mould growth at the roof area. In case of Salmonella infection, the silos should additionally be disinfected
Bad hygiene of the feed systems in the stable: feces in the pans and feed remains in the pans.
Water supply systems at a farm can purchase the water from either public supply systems or private wells. The public water supply is normally safe for use as long as the farm's 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. When medication is applied through drinking water, nipple systems should be monitored closely for adverse effects like slime formation inside the tubes.
Except traditional cage housing systems, all others 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 or removed, but too dry conditions may lead to a very dusty environment for the animals.
Roughly three farm systems are used: 1.Cages are used for individual housing of hens and/or cocks, 2. Free run or deep litter where both animals are running freely and 3. Free range where animals have access to the outside world.
At GPS, PS and egg production farms 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 or distribution of normal shell eggs these eggs can cause undesired contamination of brooders or hatchers or may present hazard for the consumer.
Laying nests should be checked frequently for presence of cover materials and damaged eggs. Egg conveyer belts which are used in larger farms should be clean. Every stable should have its own equipment, which should be well maintained and cleaned frequently. Equipment for vaccination often is used for every flock at a farm, which requires very strict hygiene.
Trays for eggs should be either cleaned and disinfected plastic or new one way cardboard ones. Lorries for transportation should be clean and bacteriologically safe. When large hatchery trays are used they should be disinfected.
Layer cages allow easy control for farmers, although the lower and upper rows of cages are difficult to reach for inspection
Equipment should preferably stay in the house, and should be maintained and cleaned frequently.
Often the hygiene standards at organic farms are under pressure, since the animals are allowed outside which opens the possibility for undesired guests to enter the house. Moreover the hens can come in contact with infectants in the direct environment of the house. Since drugs are only allowed occasionally, diseases must be avoided according to the prevention theory. Selection of animal species that are adapted to the environment is preferred above the use of medicines.
Other farm animals
Smaller 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 poultry stock first, followed by the other species.
As the poultry stock is closer to the top (e.g. GPS stock), animals are more valuable, and animal health is a very important issue. Vaccinations should preferably be carried out under veterinary control. Avoid spread of vaccines amongst flocks of different ages.
Stocking and drying of manure
At GPS, PS or egg production farms, manure is often dried at the farm which may lead to cross contamination between different flocks. The best alternative is separation of the manure stock from the stables, and keep out pest animals.
Deep pit manure systems may lead to problems with flies and other insects, since the manure stays underneath the cages for a long time. Manure belts are frequently emptied, and the manure is stored outside the housed.
Stressors such as replacement of cocks at GPS or PS flocks, 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. In broiler farms thinning may also cause stress.
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. This is also valid for loading crues in broiler farms, especially at thinning.
- effect regular C&D