HATCHERY SANITATION FOR QUALITY CHICKS PRODUCTION
INTRODUCTION
Hygiene is an important aspect of hatchery design and management. Good hygiene is required for maximum hatching rates and chick quality. The protection from contamination of hatching eggs and day-old chicks or poults, particularly in the light of specific disease controls (e.g. those concerning Salmonella), is becoming increasingly relevant in the operation of hatcheries. Protection of the workforce from contamination is also becoming a more prominent concern.
With the progressive development of the poultry industry within a country, hatcheries become larger in size, and many operate continuously throughout the year. This situation is the result of the large increases in the number of eggs set for incubation and hatched. To meet demand and utilise expensive equipment more economically, more than one hatching per week may be planned.
The marked increase in output of day-old chicks necessitates a corresponding increase in related services and operations. These services include the movement of personnel and vehicles within and around the hatchery building. All these factors demand precise planning of hatchery operations to ensure maximum sanitary standards. The work flow implicit in hatchery design supports the production of clean hatching eggs and the despatch of strong, disease-free chicks, which are the basic aims of poultry hatcheries.
SOURCE OF CONTAMINATION AND
PREVENTIVE MEASURES
A major source of contamination within the hatchery is the poor sanitary condition of the hatching eggs on arrival at the hatchery. The level of cleanliness of the hatchery therefore depends to a large extent on the hygienic standards of the laying flocks and, in particular, on the regular and frequent collection of eggs. In each hatchery, it should be mandatory that only clean eggs be set. These eggs should be fumigated on the farm as soon as possible after collection to enable destruction of microorganisms before these have time to penetrate through the eggshell. The fumigated eggs must be packed in cases and ‘filler flats’ which are also free from dust and dirt. Hatchery personnel should adopt routine sanitary procedures, both in the hatchery and on the supply farms, to prevent the development of hatchery sanitation problems, rather than attempting to solve such problems after they have arisen. All outside hatchery doors should be kept closed and locked to prevent unwanted visitors from entering. Staff and authorised visitors should shower and change clothes (putting on hair nets, overalls, boots, etc.) prior to entry.
Contamination of the hatchery can also occur from the immediate environment. The spread of Newcastle disease virus from contaminated vehicles has been recorded. Consequently, the importance of locating the hatchery as far as possible from other buildings which house livestock, and poultry in particular, requires special emphasis. The disinfection of vehicles and outdoor equipment must also be an integral part of routine hatchery sanitation.
There are many areas in the hatchery where dust and dirt readily accumulate, e.g. the spaces between, behind and on the top of incubators and hatching machines. Dust and dirt can often be found inside air ducts. In hatcheries with poor ventilation systems, moulds and pathogenic bacteria (usually originating in the washing and disposal areas) can be carried by the ventilation system into the incubator rooms. Spores of moulds may
remain viable at room temperature for 18 months or more in hatchery dust. Embryos may become infected with bacteria and moulds during incubation, and newly hatched chicks are very susceptible to infection with various microorganisms (e.g. Salmonella spp., Escherichia coli, Pseudomonas spp., Proteus spp. and Aspergillus fumigants) . Cracked eggs facilitate a marked increase in eggshell penetration by Salmonella spp. A single infected egg can contaminate large batches of clean eggs when the egg is accidentally broken, or as hatching occurs . Infection by E. coli can also occur in a similar manner .
As an example of the magnitude of the microbial problems which may be faced in a hatchery, it has been found that a single egg can carry up to 30,000 microbes on the shell. The increase in numbers of microorganisms inside the hatchery is aided by the relatively high working temperature and humidity.
The process of hatching and the work involved in removing chicks are accompanied by a massive increase in numbers of microbes, which originate from dead embryos, `pipped’ eggs, hatcher dust and fluff, and from the activities of personnel. These factors influence the level of microbial contamination of the chicks as they hatch, and affect their subsequent health and survival potential, especially during the first few weeks of life. The hatchery and the surrounding environment should be cleaned regularly.
Within the operating parts of the hatchery, the surface finish of floors, walls and ceilings must be ‘hard’, and suitable for washing by water applied under pressure. Similarly, the immediate surroundings of the building must be constructed of concrete or a similar impervious material, with adequate drainage. The drainage from inside and outside the hatchery must be designed to protect the environment from any pathogenic bacteria, viruses and moulds carried in the effluent.
CLEANING AND DISINFECTION
Effective cleaning and disinfection programmes are vital in the poultry hatchery. These programmes control key organisms, such as Salmonella spp., Pseudomonas spp., Proteus spp., E. coli, Staphylococcus spp., Streptococci spp. and Aspergillus spp. , and concentrate on four key areas of concern: the egg, surfaces which can contaminate the egg, air-borne contaminants, and movable equipment and personnel.
Washing is necessary prior to disinfection, as the presence of organic matter (e.g. soil, dust, feathers and litter) protects harmful organisms from the action of chemical disinfectants. In some instances, this organic matter will actually inactivate certain types of disinfectants. An adequate supply of water is therefore necessary for the cleaning of hatching areas and machines, the chick boxing area, and some permanent and movable equipment. Cleaning of floors, walls and equipment requires adequate and suitably-
located drainage for waste water. Incubators must be cleaned after each transfer of eggs. This can be accomplished by scraping, vacuuming and mopping the floors, and wiping down wall areas and fan blades at the same time. Exterior surfaces require damp mopping at least once a week. The top surfaces of incubators should never be used for storage. Once yearly, each machine should be emptied and thoroughly cleaned. To avoid incubator contamination, eggs should be transferred before egg pipping starts.
Avoid moving or transferring chicks and cleaning hatchers at the same time in the same hatcher room. Cleaning should not begin until all chicks have been removed from
the hatcher room. Proper cleaning of the empty hatchers is necessary, after each hatching, to avoid contamination. Machines may be swept or vacuumed to remove loose debris. Use of a foaming detergent will aid in the removal of stains from the interior walls of the hatchers. Performed properly, scrubbing, rinsing and disinfection will yield a clean machine. Humidity wicking should be replaced after each hatching, and hatcher gaskets should be checked and replaced if necessary. Extra attention should be paid to fan blades, as dirty, rough blades cannot move the correct amount of air. Hatcher fan blades become easily worn, even in normal use, and should be replaced annually. A bent blade causes excessive vibration and does not move the air properly. Some fresh air from outside is necessary to aid the drying of the room and thus prevent the growth of mould and bacteria.
The air compressor should be located in a clean, dust-free room, as this air is channelled to all areas of the hatchery through hoses and humidifiers. Humidifiers in all areas must be kept sanitised to prevent the spread of harmful organisms. Evaporative coolers should be cleaned every week. Sumps on these coolers must be drained and scrubbed, and disinfectant should be added to the sumps when refilling. Heaters should be washed or ‘blow-cleaned’ to prevent dirt and dust from collecting.
All equipment must be properly cleaned and disinfected. Certain equipment (e.g. fibre egg trays and boxes) cannot be cleaned with water under pressure. Plastic egg trays, wooden egg boxes and plastic chick containers can be cleaned easily with water and detergents and, if necessary, these pieces of equipment may be given a final disinfection or fumigation. Another necessary precaution against the dissemination of disease agents involves labelling egg boxes and egg trays with an identification code, so that these may be returned to the flock which produced the hatching eggs when cleaning has been completed. Washer nozzles should be removed and cleaned frequently to ensure that these are in good working order. Washer pump motors should be switched off whenever filter screens are removed for cleaning, as running the pumps with the screens out allows debris to pass through the pump, blocking the nozzles. All flats, trays and racks should be wetted down and soaked for an adequate period prior to washing, thus enabling the washer to perform a more effective cleaning job. Water in the washer tank should be at 47-52°C (120-130°F) and should be changed frequently during the day to prevent equipment from being washed in dirty water.
An extra hatcher rack or ‘dolly’ in the washroom eliminates the need to stack trays on the floor at the exit end of the washer, thereby preventing re-contamination after washing. All washed trays and racks should be thoroughly disinfected before leaving the wash area. A water hose fitted with a common domestic spraying nozzle is suitable for this purpose. Clean trays and racks should never be put into a dirty hatcher room. Egg trays, setter trays or flats, and chick boxes must be thoroughly cleaned and disinfected before re-use or return to the farm.
Removal of hatchery waste is a very important consideration, and an efficient method of disposal must be planned. Vacuum disposal systems are now becoming fashionable, and space needs to be available for this equipment. Some areas within the hatchery do not lend themselves to the use of water under pressure, e.g. the top surfaces of incubators and hatching machines, electrical equipment and controls, ledges, tables and other horizontal surfaces. These surfaces readily collect dust and debris in which microorganisms multiply rapidly and should therefore be reduced to a minimum. The remaining horizontal surfaces must be cleaned regularly. For this purpose, a commercial industrial vacuum cleaner may be used. Disinfection may then be performed using a
disinfectant solution in spray form . For cleaning measures of this kind, an aerosol generator is useful. It follows from the above that routine fumigation alone is no longer sufficient. Nevertheless, fumigation using formaldehyde (formalin) has proved to be a very effective means of destroying microorganisms on eggs, egg cases, setters, hatching machines and fibre chick boxes, provided that these items have been subjected to preliminary cleaning.
FUMIGATION USING FORMALDEHYDE
Requirements for proper fumigation
The following requirements must be met if maximum germicidal activity is to be obtained from formaldehyde:
a) Temperature: the maximum effect is achieved in the temperature range of 24-38°C.
b) Humidity: this is essential for maximum effect, and a ‘wet bulb’ reading of 20°C or higher is recommended.
c) Time: the time required to kill the microorganisms depends on the temperature, the humidity and the concentration of formaldehyde.
d) Concentration: the use of potassium permanganate to liberate formaldehyde gas is desirable, as this produces an instantaneous expulsion of gas, giving maximum concentration.
To produce the fumigant, potassium permanganate should be mixed with formalin in a ratio (w/v) of 2:3. When the correct ratio of formalin and potassium permanganate is used, a dry brown powder remains after the reaction is completed.
Recommended application rate
An application rate of 53 ml formalin and 35 g potassium permanganate per m3 of space is recommended. These amounts are effective in fumigation for 20 min at the recommended temperature and humidity. To calculate the amounts of chemicals necessary, the internal dimensions (i.e. length x width x height) of the incubator, fumigation cabinet or fumigation room should be measured. The space occupied by trays of eggs or articles to be fumigated need not be taken into consideration.
Neutralisation of formaldehyde gas
Formaldehyde gas may be neutralised in 10-15 min using ammonium hydroxide at an amount equal to half the volume of formalin used.
Precautions
Formalin will lose strength unless maintained at room temperature in a tightly sealed container; it should not be stored for long periods, as a white precipitate (paraformaldehyde) will form. If this occurs, the precipitate should be thoroughly mixed in before use. If storage is necessary, formalin should be kept in small, completely filled containers. When mixing with potassium permanganate for fumigation, always add the formalin to the potassium permanganate, never the reverse. Formaldehyde at bactericidal concentrations is very irritating to the eyes, nose and throat. Hatchery personnel should use a respirator and avoid unnecessary exposure to the gas. An appropriate container should be used to release the gas. The sides of the container
should slope outwards to avoid an excessive build-up of heat, which could ignite the formaldehyde. The container should be made of heat-proof material, such as metal or earthenware, and should be sufficiently large to prevent the chemicals from boiling over. Chicks or poults should not be exposed to the full concentration of formaldehyde gas.
Hazards of fumigation
The human health risks of formaldehyde fumigation are a cause of great concern. Use of formaldehyde is prohibited in some countries. Human exposure should be avoided, and gas masks and protective clothing are essential .
Fumigation of eggs
To reduce microbial penetration of the shell to a minimum, eggs should be fumigated immediately after collection, and preferably while they are still warm. The fumigation room or cabinet should be airtight, and should be equipped with a fan to circulate the formaldehyde gas during fumigation and expel the gas from the building when fumigation is completed. The eggs should be collected loose in wire baskets or placed in plastic trays in a manner which will permit air circulation and exposure to the formaldehyde gas. The temperature and humidity should be at the recommended levels. The fumigation time should be at least 20 min. Experience has shown that fumigation for 60 min will not reduce viability of the eggs at hatching. The type of facility and fumigation procedure used with eggs, egg trays and cases at the hatchery is the same as for fumigation of eggs on the farm.
Fumigation of eggs in setters
Eggs should be fumigated within 12 h after setting, when the temperature and humidity return to normal operating levels. The setter doors and vents should be closed, but the circulation fan should remain in operation. After fumigation for 20 min, the vents should be opened to the normal operating position to release the gas.
Warning: Eggs which have been incubated for 24-96 h should not be fumigated, as this can result in embryo mortality.
Fumigation of hatchers
Following the removal of all chicks and the cleaning and disinfection of the empty machine, the disinfected egg trays are replaced and the machine is prepared for the next batch of incubating eggs. The doors and vents should be closed, and the temperature and humidity returned to normal operating levels. Fumigation time should be at least three hours, or preferably overnight, using the standard amounts of formalin and potassium permanganate.
Warning: The above fumigation procedure applies to a machine in which there are no eggs. Eggs and chicks cannot be fumigated using the above fumigation time.
Fumigation of eggs in hatching machines
Fumigation of eggs in hatching machines is a common practice in certain areas and under certain conditions. The eggs should be fumigated after being transferred to the hatching machines and before 10% of the chicks have begun to break the shell. After transfer of the eggs, the hatching machines are permitted to return to normal operating temperatures and humidity. The ventilators are closed and fumigation is conducted with the hatching fans switched on. The standard amounts of formalin and potassium permanganate are used. Fumigation time is 20 min.
Neutralisation of formaldehyde gas
Formaldehyde gas can be neutralised using a 25% solution of ammonium hydroxide; the solution should be applied at a rate of not more than half of the volume of formalin used. The ammonium hydroxide should be spread on the floor of the machine and the doors closed quickly.
Use of formaldehyde powder (paraformaldehyde) as a fumigant
Paraformaldehyde may be used as a source of formaldehyde gas for fumigating eggs and egg cases. This method is effective, provided that the temperature and humidity are at the recommended levels. The minimum temperature should be 24°C, with a wet bulb reading of at least 20°C. Paraformaldehyde should be used at a concentration of
10.5-13 g per m3. The conversion formula is 10 ml formalin to 2.5 g formaldegen (paraformaldehyde) powder. The generator should remain in operation until all the fumigant is released. The door should be opened to allow the formaldehyde gas to escape, or the gas should be neutralised using ammonium hydroxide at a rate of
27 g per m3.
USE OF DISINFECTANTS
Ninety percent of hatchery sanitation is dependent on design of the premises, good management of the hatchery and of supply flocks, cleanliness, and a programme whereby dust is removed and prevented from reaching the hatching areas. The remaining 10% requires the additional hygienic measures provided by fumigation and disinfection . A disinfectant, whether used as a solution, gas or aerosol, cannot compensate for faulty cleaning or for a hatchery which is inadequately designed to permit a thorough cleaning programme. Hygiene control in a hatchery is essentially a result of cleanliness complemented by disinfection. To date, formaldehyde has been the fumigant recommended for use in hatcheries due to its efficacy and ease of application . However, the use of this product presents a serious hazard for human health and safety, and it is possible that the use of formaldehyde will be further restricted, if not prohibited, at some time in the future . Suitable alternative sanitisers must therefore be found for use in the hatchery environment, including for disinfection of incubating eggs. When eggs are properly washed, sanitised and dried, the level of bacterial contamination on the shell is greatly reduced. Inadequate egg-washing can allow microorganisms to enter the egg.
GENERAL RECOMMENDATIONS
A hatchery must be sufficiently isolated from risks of infection.
The hatchery and the premises must be designed and maintained to ensure that animals, rodents and wild birds are unable to enter.
Entry to the hatchery should be through a hygienic barrier (personnel should take a shower and change clothes).
Good hygienic standards should be maintained in the hatchery through an approved sanitary programme (regulation of temperature and ventilation; cleaning, disinfection and fumigation of eggs, rooms, installations and equipment, etc.). Re-contamination should be prevented by prohibiting movement of equipment or personnel from dirty to clean areas.
At any one time, the eggs in the hatchery should originate from one species of poultry only, and should be marked with the identification number of the breeding farm.
Any waste matter or refuse must be collected immediately and removed in an appropriate manner.
Hatchery workers should not be employed simultaneously in poultry processing plants, markets, or in poultry-raising or -handling operations.
Sexing and vaccination of chicks should be performed in a special room, equipped with a washbasin providing hot and cold running water and with the means to disinfect hands. Instruments and equipment used should be disinfected before and after use.
All data and activities must be recorded daily in the hatchery register or diary.
Chicks should be despatched from the hatchery in new, closed containers of disposable type.
Chicks leaving the hatchery should be conveyed in clean, disinfected vehicles which are used for this purpose only.
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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