CARE OF HATCHING EGGS ON BREEDERS FARMS

CARE OF HATCHING EGGS ON BREEDERS FARMS

Compiled & Edited by-DR. RAJESH KUMAR SINGH, (LIVESTOCK & POULTRY CONSULTANT), JAMSHEDPUR, JHARKHAND,INDIA
9431309542, rajeshsinghvet@gmail.com

 

At the time a fertile egg is laid, there is already a small embryo floating on the yolk. The vitality of this embryo must be preserved during storage until the point in time when the incubation process starts. To achieve this, the eggs are handled carefully and temperature fluctuations avoided as much as possible under practical conditions . Beside this common practice, specific management procedures may help to minimise the loss of hatchability during extended egg storage.

Eggs laid by the hens without mating the cock will not hatch out, as they are infertile without any germ inside to develop into a chick. Within 21 days a minute germ is transformed into a chick, by a rapid development and change within an egg. All eggs laid by a hen are not fit for hatching. Suitable eggs that could be hatched-out should be carefully selected on the following basis.

Fertility—————-

 

Fresh eggs collected from vigorous and well matured hens, 5- 7 days after mating and within 2 days of separating the cock will be fertile enough for hatching. Eggs collected immediately on letting in the cock for mating or long after the separation of the cock the egg  may not be fertile.

 

Egg size and shape——————–

 

The size of the eggs used for hatching is important because the size of the chick hatched highly depends on the size of the egg. The eggs for setting should be neither too big nor too small, depending upon the breed. It is always desirable to select eggs of about 58 g each. Uniform sized and oval shaped eggs are good.

 

 

Egg shell————-

 

The egg shell should be of uniform thickness, texture and colour so that the warmth can uniformly spread during incubation. In case of white shelled eggs, all eggs for incubation should be free  from tints. For brown coloured eggs medium and dark brown eggs: hatch better than the light brown eggs. When shell texture is poor due to deficiency of calcium or vitamin D, it results in low hatchability. All eggs should also be tested for cracked shells, as they should not be used for incubation.

Egg quality——————-

 

Eggs should be fresh and not stale, collected as early as possible after laying, at any rate within a week of laying. Very fresh eggs just laid on the day of setting may not be advisable to be set unless they attain the room temperature before setting. Eggs of 2- 4 days old are excellent.

 

 

 

 

Deformity——————-

 

Eggs with any deformity such as ridges, encrustations, projections, depressions, cracks or stains should not be selected. Very thin shells may break during turning and will not retain uniform temperature for embryo to develop. If the shell is very thick, there will be difficulty for the chick to chip it with its tender beak and come out.

Soiled egg—————–

 

Soiled eggs should not be washed in water before setting, as washing with water opens up the pores and this interferes with the hatching results. If the dirt is not excessive, it should be removed with a knife. Highly soiled eggs should not be used.

Storage—————-

 

Eggs collected for setting should be kept in a dry, cool and airy place in order to get the best results. In hot weather, eggs should not be kept for more than 3 days and in winter or in hilly areas it can be kept up to 10 days.

As eggs absorb odour very easily, it is not good to store them near smelly substances like onion, garlic, kerosene etc. Eggs should be stored in a cool place with the broad ends up. Eggs shaken very much during transport will not be good for hatching.

 

 

 

 

 

 

Eggs must be kept in clean conditions and at the correct temperature and humidity to achieve the best hatchability. Satisfactory procedures for collection, disinfection, cooling, storage, and incubation of the
eggs should be in place, and each process should be carried out so that embryonic development is not compromised.

 

 

Why Do Hatching Eggs Need Care? ————–

 

Fertilization takes place at the top of the oviduct shortly after the yolk is released from the ovary. The yolk then passes down the oviduct . As it does so, the outer layers of the egg are laid down, and the fertilized germinal disc grows and develops. By the time the egg is laid, it contains a germinal disc that has been growing for 24 hours as the egg is formed around it ..

 

After the egg is laid, it must be cooled to suspend any further development until the egg is set at the

hatchery. The care given to hatching eggs has to meet the needs of these dormant (but living) embryos. The egg components surrounding them have to be maintained in good condition. Uncontrolled fluctuations in egg store temperatures will cause stop-start growth of the germinal disc, which will reduce hatchability. Recent studies have shown that if eggs are to be stored for more than a week, it can be beneficial to warm them up to incubation temperature for short periods during storage.

 

The Egg’s Protection System ——————-

 

The egg provides a multi-layered system of protection from microbial contamination . The cuticle, egg shell, shell membranes, and some of the proteins in the albumen act as either physical or chemical barriers to prevent microbes gaining access to, and growing in, the egg contents. The shell of the egg is a porous structure. Pores run from the surface right through the shell .
These pores are needed to allow oxygen into, and water and carbon dioxide out of, the egg as the embryo develops.

 

The entrance to the pore on the egg shell surface is protected by the cuticle. The cuticle is a thin protein

coat that allows gases, but not micro-organisms, through. This coating provides the egg contents with some protection from microbial penetration. However, the cuticle does have one point of weakness. Immediately after the egg is laid, it is still not completely formed (this is why the shell surface looks wet and under magnification, it has an open, sponge-like appearance). The cuticle hardens to a flatter, flake-like surface within 2-3 minutes of the egg being laid. Until this process is complete, it is easy for microbes to penetrate the cuticle and then pass down the pores and into the egg .Understanding the structure of the egg shell helps to explain why certain procedures used on the farm to clean eggs can make contamination problems worse. For example, if slightly soiled eggs are buffed or scraped to remove the surface dirt from the shell, some of the dust that this produces will be packed into the shell pores and block them. Blocked pores will impair gas exchange, and as a result, limit the oxygen available to the developing embryo. More importantly, pores blocked with contaminated material will increase the risk of contamination. In addition, buffing or scraping the shell surface will remove the protective cuticle, making it easier for bacteria to enter the egg.

 

Contamination problems can also be made worse if the eggs become wet after collection for any reason. Liquid will run into the pores of the shell, carrying any bacteria on the shell surface with it. This is especially likely to happen if the egg contents are cooling. Cooling creates a partial vacuum within the shell, making it more likely that any surface liquid (and microbes) will be drawn in through the pores and is why condensation on the egg shell causes so many problems.

 

NB-•  Eggs should be maintained in a clean state between lay and packing.

• Methods used to remove surface dirt should be gentle so as not to damage the cuticle or block the egg shell pores.
• Condensation on the egg surface should be avoided as it can lead to contamination problems.

 

 

Best Practice for Care of Hatching Eggs ———————————

 

Egg Collection ————————

 

• Manage the flock to minimize the number of eggs laid on the floor .
• Keep the insides of the nests and any collection belts free of litter and droppings. As a minimum,

nests and collection belts should be brushed clean at least once a week and checked for dead birds

daily. Collect nest eggs a minimum of 4 times a day, adjusting the exact timings so that no more than 30% of the eggs fall in any one collection (any more will increase the incidence of dirty or cracked eggs). The majority of the eggs will be laid in the morning and collection intervals should be managed accordingly. The nests and egg collection belt should be cleared at the end of the working day to minimize the number of eggs left over night.

• Collect floor eggs separately. They should be collected as often as possible (more often than nest eggs) and should be kept separately from nest eggs so that the hatchery can manage appropriately the contamination risk they present.
• Monitor the numbers of floor and dirty eggs and adjust management factors to minimize them .

 

Egg Packing and Selection –

 

• If eggs are being packed straight on to setter trays, select and pack the eggs immediately after each collection.
• If eggs are to be boxed, they should be cooled to egg store temperature prior to boxing. Reject small

eggs (minimum weight will be an economic decision), cracked or damaged eggs, eggs with gross shell abnormalities, double-yolk eggs, soft-shelled eggs, and any eggs that are more than 25% covered with dirt or droppings (or exceed levels of soiling stipulated by hatchery or regulatory requirements). Record numbers rejected in each category and monitor them.

• Avoid wet egg disinfection methods – fumigation with formaldehyde is best.
• If eggs do become wet, let them dry before fumigating them or placing them in a cold egg store.
• Immediately after each tray of eggs is packed, place it in a rack in the egg store. Trolleys should be packed from the bottom up. This order of packing will avoid re-warming cooled eggs by placing warmer eggs beneath them in the trolley .
• Once an egg trolley has been placed in the egg store, it should stay there. Fill a partial trolley by taking trays of eggs into the store to finish loading, not by taking the trolley out of the store.
• Eggs or trolleys should not be wrapped in plastic until they have cooled to egg store temperature

 

Egg Disinfection ——————-

 

Fumigation with formaldehyde remains the most effective (and preferred) method for disinfecting the

shell surfaces of hatching eggs. Provided fumigation is performed correctly, it achieves excellent kill rates of micro-organisms on the shell surface without wetting the shell, damaging the cuticle, or damaging the embryo inside the egg. Despite its effectiveness, some countries now prohibit the use of formaldehyde because of the potential risk to human health and safety if it is not used correctly.

Many different chemicals and application methods have been investigated as alternatives to formaldehyde fumigation. None have proven to be as effective, either because they kill a more limited range of microorganisms, because they have to be used in solution, because they damage the cuticle, or because they are detrimental to embryo survival. Follow these guidelines when using formaldehyde:

• Follow the appropriate safety precautions when using formaldehyde. Always adhere to local rules governing the health and safety of farm workers when using formaldehyde.
• Fumigate eggs with formaldehyde at least once before they leave the farm.
• Make sure that the eggs are well separated on plastic egg or setter trays; cardboard tends to absorb the gas.
• Ensure the fumigation room is well sealed during fumigation and allow at least 20 minutes for the gas to circulate after it has been generated.
• Heat 43 ml formalin (37.5%) per m³ (1.5 oz per 11 ft²) of fumigation room.
• Ensure room temperature is a minimum of 24°C (75.2°F).
• Ammonia can be used to neutralize the formaldehyde before the cabinet is exhausted.
• Run a circulating fan during fumigation to help circulate the fumigant gas between the eggs; switch the fan off before exhausting the formalin at the end of the disinfection period.
• Make sure that all the gas is completely exhausted from the room before workers re-enter to move the eggs. This step is less urgent if the gas is neutralized first, but should be re-checked periodically using an appropriate meter.

 

Assessing Alternatives to Formaldehyde—————

 

Where formaldehyde fumigation is not permitted due to local health and safety regulations, alternative methods of disinfection need to be found. Many alternatives to formaldehyde have been tested over the years. All have disadvantages, and most have to be used with the same due care and attention to operator safety as formaldehyde.

There are many products sold as being suitable for disinfecting hatching eggs (including hydrogen

peroxide, peracetic acid, quaternary ammonium and chlorine disinfectants). Before implementing any new method or chemical for disinfecting hatching eggs, it is strongly advised that their effectiveness is thoroughly tested, making sure to closely follow the advice of the equipment and chemical suppliers.

Factors to consider when testing alternatives to formaldehyde include:

• The egg shell bacterial counts before and after treatment.
• Egg content bacterial counts after treatment.
• Impact on cuticle cover (which can be seen under UV light).
• Hatchability.

 

Hatchability tests should involve at least 1,000 eggs per treatment group, split from a single collection of
eggs. Half the eggs should be treated according to current methods, and the other half by the proposed new treatment. The test should be repeated over a range of flock ages and egg storage durations.

 

Cleaning Soiled Eggs ———————

 

Provided any surface dirt is not extensive, it can be removed by gently flicking the dirt off with a finger nail, or for soft droppings, by gently wiping off with a clean paper towel. Care should be taken not to contaminate clean parts of the egg. The eggs should then be disinfected (ideally by fumigation with formaldehyde) and sent to the hatchery clearly marked as dirty.

 

The washing of hatching eggs is not good practice. But under some conditions, washing eggs may be unavoidable. If washing eggs is necessary, the following applies:

• Use a washer that sprays the eggs with warmed disinfectant solution, rather than one that relies on the eggs being immersed in the solution.
• Wash water should be 41°C (106°F) to ensure that the wash water is always warmer than the warmest eggs in the collection .
• Record and monitor the process, taking care to monitor temperatures and the frequency with which the washing water is changed.
• Make sure that the disinfectant concentration does not fall below the recommended minimum effective concentration level and that the washer solutions are replaced after each batch of eggs to maintain disinfection concentration.
• Allow the eggs to dry before they are cooled in the egg store.
• Fumigate washed eggs when they are dry.

 

 

Egg Storage Conditions ——————-

 

After the egg is laid, it should be cooled so that cellular growth of the embryo is suspended. Ideally,

hatching eggs should all be set within 7 days of lay. Storage for longer than 7 days will result in a loss of hatch due to embryo cell death and a decline in internal egg quality, especially albumen quality. When longer storage is unavoidable, a cooler storage temperature will help to keep the yolk and albumen in good condition.

 

Temperature ————

 

• Keep egg temperature constant once the eggs are cooled and watch for variable storage temperatures throughout the day and when doors are left open. It is important to coordinate temperatures with those used in transport to, and storage at, the hatchery. This will avoid fluctuating temperatures and condensation.
• Storage temperatures need to be set at a level that will maintain internal egg quality and keep the

dormant embryos alive – long storage should be at lower temperatures than short-term storage .

• On farm storage temperatures should be managed so that the temperatures are adjusted when the average storage duration changes.
• Keep the farm store 2°C (4°F) warmer than the hatchery store, with the truck temperature intermediate between the two. This will help to avoid any condensation forming on the eggs.
• Do not blow cooler or heater fans towards eggs.
• The eggs do not need a sequence of different temperatures at the hatchery. For example, if a batch of eggs is to be stored for 14 days, embryo survival will be best if they are held at 15°C (59°F) or less for the whole storage period.
• For storage over 14 days, 12°C (54°F) can work well, but only if great care is taken to avoid condensation when eggs are moved to a warmer environment.

 

 

 

 

Table 20: Relationship between length of egg storage and temperature of egg store.

 

 

 

Storage Period (days)	Temperature of Storage* oC (oF)
1-3	20 (68)
1-7	15 (59)
> 7	15 (59)

 

* Humidity between 70 and 80%

 

 

Humidity—————

 

• Ideally, egg store humidity should be held between 70 and 80% RH, to prevent the eggs losing too much moisture during storage.
• If cold eggs are moved into a warm, humid atmosphere, condensation will form on the egg surface,
• Make sure that the water in the humidifier is clean (static reservoirs can encourage bacterial growth)
  and that spray nozzles are maintained properly so that they produce a fine mist of water and not large
  droplets.

 

NB—

 

• Nest cleanliness and regular/frequent egg collection are extremely important.
  Any egg laid onto dirt or droppings will become contaminated.
• There will be microbes even on the shells of clean hatching eggs. Unless

there is effective disinfection of the egg shell surface before eggs arrive at  the hatchery, they present a risk to hatchery hygiene and embryo survival and health.

• Formaldehyde fumigation is the best method for disinfecting egg shells.
  Ensure that temperature, humidity, and air circulation are appropriate for effective fumigation.
• Follow safety procedures.
• If an alternative to formaldehyde does need to be used, to be comparable to formaldehyde fumigation, the new method should kill 99% of shell surface
  bacteria, viruses and molds; give no increase in egg content bacterial counts; cause no or minimal cuticle damage, and give the same or better hatchability
  in both young and older flocks and after long egg storage.
• Monitor and record egg washing procedures. If the recommendations for washing eggs are not achieved, the level of rots and contamination in the washed eggs will be high, with poor hatch and chick quality.
• Adjust on-farm storage temperatures for the oldest eggs. Fresh eggs will

hatch normally if kept at lower temperatures, whereas the hatch of longerstored eggs will suffer if kept too warm.

• If there is condensation on the eggs, do not fumigate them and do not put them into the cooler until they have dried.

 

 

Problems Resulting in Rots and Bangers ————————

 

 

 

If the hatchery is experiencing an excessive number of rots and bangers, check the following:

• The number and severity of dirty eggs being produced. Make sure nests and collection belts are checked regularly and cleaned immediately if a problem is spotted.
• That floor eggs are not washed and then mixed with nest eggs.
• That eggs are not collected or packed into dirty trays.
• That the shell quality (increase in rejected or cracked eggs) is normal for the age of the flock. Shell

quality can be damaged by inappropriate feed or respiratory diseases and will show up as a sudden increase in rejected and/or cracked eggs.

• That egg washing and disinfectant media are 41°C (106°F).
• That washed eggs are not mixed with clean eggs.
• That wet eggs are not being placed in the egg store.
• Condensation on the egg surface as this will increase rots and bangers.

On-farm humidification is not necessary and needs a great deal of care and attention to make sure that it is not a cause of contamination.

 

NB-•  If there is an excessive number of rots and bangers in the hatchery, investigate potential causes and take required action.

 

Longer Periods of Storage ——————-

 

Broiler hatching eggs should normally be set before they are 7 days old. If longer storage is unavoidable, hatch can be improved by using short periods of incubation during egg storage (SPIDES).

 

 

Hatching egg collection and care

 

 

• In slat or deep litter system, keep nest boxes at the rate of one hole for 4 to 5 hens at 18-20 weeks of age. Close the nest holes during night time, to discourage broodiness and soiling of nest material.
• Introduce males around 22 weeks of age at 8 cocks/ 100 hens or as per the recommendation of the principal breeder.
• Collect hatching eggs when they reach at least 48-50g weight or from 25 weeks of age whichever is later.
• Collect eggs at hourly interval during forenoon and once in 2 hours in the after-noon in deep litter and wire floor sheds. In cages collect eggs 2 or 3 times a day.
• Separate clean, soiled dirty, broken, misshapen and abnormal eggs soon after collection.
• Save clean eggs with sound shell, shape and size for hatching; without any cleaning.
• Dry clean soiled eggs with the help of a sand paper, dry cloth or cotton and also save them for hatching.
• Do not practices wet cleaning of eggs. Discard other eggs which can be sold for table purpose.
• Fumigate hatching eggs with formaldehyde gas at 3 X concentration and store in an egg store room, until 6 hours before setting.
• Do not store hatching eggs for more than a week. In case of cage system, netlon or rubber mat is placed over the cage floor to prevent hair cracks (checks) in hatching eggs. Otherwise, plastic coated steel mesh is used as cage bottom

 

 

Factors affecting hatchability of eggs—————-

 

Hatching of eggs is affected by several factors.

• Age of breeding birds. Young birds Eggs lay fewer eggs with low fertility. This increases with subsequent seasons reaching their potential in the third lay.  After 17 years of age, the production of females’ declines.
• Herd ratio. High number of female against males is likely to result into birds laying infertile eggs. Ideally one male should serve 3 females.
• Nutrition of the female. Nutritional deficiencies especially calcium leads to birds laying eggs with weak shells. Such a shell is porous allowing penetration of microorganisms that kill the embryo. Therefore Calcium supplementation is recommend for laying birds.
• Poor handling of eggs.Contact between the collector body and the eggs may lead to embryo   mortality due to contamination. During transportation care should be taken to avoid excessive shaking of the eggs.
• Worm infestation.The Tape worms are the most common in ostriches due to their feeding habits. The worms compete with the birds for the essential nutrients.

 

 

Reference-On Request