موضوعات للمهتمين بصناعة الدواجن Topics for poultrymen( Breedrs, Smallholders, Resarchers, Students ) in poultry industry

 

Incubating Eggs

Whichever model of incubator you have available, it is vital to refer to the manufacturers instructions supplied with it. (replacements are available for almost all but the Hannaford Paraffin models! ) These have been written to give the best results with that particular model and some aspects may not be applicable when using other incubators. For this reason, it is not easy to provide detailed guidance which will be appropriate for working with all types of incubator. These notes, therefore, are a general guide only

Using an Incubator

Place the incubator on a level surface in a position which is not prone to vast fluctuations in temperature and humidity, i.e., out of draughts, direct sunlight and away from central-heating radiators ( Sheds and barns good ....bedrooms bad unless you like the perfume of an exploded rotten egg !). Be warned that in winter, rooms become very cold at night once the heating is off. If the temperature drop is too great, it is quite likely that the incubator will be unable to maintain a steady temperature. It is therefore best to avoid incubating eggs during the coldest months if temperature regulation is likely to be a problem. Mechanical damage to the developing embryos caused by bumping the incubator may cause severe damage to delicate membranes and organs, and so the movement of an incubator is not recommended. NEVER put the incubator on carpet as the fibrous surface prevents air passage. If in doubt about airways put on two 2 x 2 wooden bars to allow a good air change

 The first task is to clean and disinfect the incubator, as appropriate. The incubator should be set up at least 48 hours before eggs are introduced to enable the correct temperature and humidity to be established and to check on the normal functioning of the thermostat

 The correct temperature for the incubation of a duckling's egg is 37.5 °C at the centre of the egg. Follow the manufacturer's instructions about setting the temperature. In some still-air incubators, there is quite a large temperature gradient inside

With some models in which the thermometer is situated at the top where the air is warmer, the recommended temperature setting may appear to be too high. However, such a setting allows for the cooler, correct, incubation temperature lower down

In most incubators, the thermometer should be positioned where the top of the eggs will be. Manufacturers' recommended temperature settings could therefore lie anywhere between 38 °C and 39.5 °C (100.5-103 °F). In normal incubator operation, temperatures may fluctuate slightly but they should not be allowed to pass outside this range. As the eggs develop, the embryos will give off some heat and this may require you to alter the thermostat setting slightly to decrease the temperature

 Once the correct temperature setting for the type of eggs to be incubated has been achieved, it is wise to tape over the temperature control to dissuade 'tweaking' the knob ! ( Yoghurt pots for small children work well ..tape over all the adjusting knobs). If possible, position the incubator so that the temperature control is hidden against a wall. Consider plugging the incubator into an audible alarm unit; this will indicate if there is a power failure for any reason. Even with such a device, it is a good idea to affix a 'PLEASE LEAVE ON' sign to the mains plug and so avoid accidental switching off by others. These may be available locally as freezer alarm plugs or can be purchased from egg incubator suppliers including Brinsea Products;& Curfew Incubators, It is also sensible to keep a temperature record card, logging readings every morning and evening. This is an easy way of checking that the incubator is functioning correctly and the card could also be used for a record of egg turning, if this is being done by hand

 A suitable humidity must be maintained to prevent the eggs drying out too quickly or losing sufficient water. All incubators have one or more water containers, trays or troughs which should be kept topped up with water to maintain an appropriate humidity, according to the manufacturer's instructions. Use hand-hot (39 °C) water to prevent the temperature in the incubator dropping too dramatically when refilled. In hard water areas boiled or distilled water means that wicks etc. last longer . Do not move the incubator while containing water. In some incubators, a piece of cloth may be needed to act as a 'wick'

 Too much humidity at the wrong time is just as bad for a developing egg as too dry an atmosphere: an egg must lose a certain amount of water during incubation if the duckling is to emerge satisfactorily

 Some incubators are supplied with a wet- and dry-bulb thermometer. The wet bulb is for obtaining readings of humidity. It is very difficult to obtain accurate readings with such a device and not recommended that they are used by beginners. It is often better to check humidity by assessing the effects on the egg,, rather than to obtain actual measurements

 Relatively accurate electronic instruments for measuring humidity (called hygrometers) are now available but the most useful of these are quite expensive. Manufacturers supply units which will control the humidity in certain of their incubators

 The eggs must have a suitable flow of air to supply enough oxygen for the embryos to develop and to remove the carbon dioxide produced. The ventilation will, however, also affect both the humidity and the temperature; a high ventilation rate will carry more moist, warm air out of the incubator

 Care should be taken to set the ventilation control according to the manufacturer's instructions. These may advise particular settings for different room temperatures. For example, in a cool room (below 16 °C), a minimum level of ventilation should be sufficient; with room temperatures >16 °C, more ventilation should normally be provided. On some incubators, a flap covering ventilation holes may need to be moved; in others, the number of holes that are left open may need to be altered

 Frequent checks should be made to ensure that nothing is preventing adequate ventilation. If using an older Curfew incubator with an insulated quilt cover that fits over the observation dome, ensure that the quilt does not block the top ventilation hole. A rolled up tube of paper inserted through the holes in the cover and quilt is a good idea

Incubating Eggs

 First, allow the fertile eggs to warm up to room temperature for at least l0 hours before placing them into the incubator. Cool eggs may lower the temperature of the incubator or be stressed if they are warmed up too quickly. If transported a long way stand blunt end up overnight to settle

In Curfew incubators, whenever eggs are to be placed into an egg tray, it is important to line the tray first with a piece of loose-weave material such as / or a dishcloth. (Hessian should be provided with new incubators; spares are available from Curfew Incubators.) Since the tray has a metal mesh, this can become very hot, so it is essential that all the eggs are on the cloth inside the tray (and also are not touching the vertical sides of the tray, if these are also made of metal). The material must not be moistened with water

 If all goes to plan, the ducklings should hatch after 28 (35 Muscovy ) days, so do not set the eggs on a Monday or they will hatch out at the weekend

 Turning helps to prevent the developing membranes from sticking to the inside of the shell. Eggs may be turned by hand, because the incubator has no automatic turn facility . Manual turning of eggs needs to be carried out at least twice, preferably three times and, ideally, five times a day for miniature breeds as the mums are naturally fidgety, including at weekends

 For incubators other than the Brinsea 'Octagon' types, as the eggs are added to the incubator, mark each one lightly with an 'X' in pencil on one side and 'O' on the opposite side. Also write the date if different batches of eggs will be added to the incubator later..... not around the waist of the egg as the duckling normally hatches here

 With most incubators, the eggs are turned through l80o around their long axis, not end to end. At each turn, move the eggs so that the 'X' and 'O' marks are alternately visible. Turning is best achieved by rolling each egg, using the finger tips, into an adjacent space. If the incubator is very crowded, it may be necessary to remove some eggs at one end so the other eggs can be rolled into the space made available. The removed eggs are then placed in the space created after rolling. Hands should be warm to prevent chilling the eggs (especially for those spring hatching

With 'Octagon' incubators, eggs can be turned without opening the incubator by tipping the entire unit from 45° on one side to 45° on the other side. However, do not worry about opening the incubator for a short time to turn eggs. Although the temperature will temporarily drop, the developing ducklings will not be harmed; after all, a broody hen does not sit on the eggs all the time

Some authorities claim that eggs should sometimes be turned clockwise and then counter-clock wise. If eggs in a manual-turn incubator are turned an odd number of times each day, they will not repeatedly spend each long, nighttime period in the same orientation

 By the 24 th day, the eggs no longer need to be turned

 Follow the guidance offered by the incubator manufacturer. Various authorities quote a wide range of suitable humidities but it is difficult to produce an exact humidity in the incubator and to measure it accurately. Ensure,,that the water tray never dries out completely and do not have a very humid atmosphere together with poor ventilation. If the eggs are in an egg tray on a dish cloth or piece of Hessian, do not add water to the material to make it damp. Also do not spray the eggs daily with a mist of water, although this has been recommended by some authorities. Ducks and Geese swim eggs don't

 Humidity levels should be varied during incubation but it is difficult to give precise advice. As a rule, during the first half of the incubation period, the humidity should be at a low to medium level; the second half requires a medium level of humidity. Some authorities recommend a dryer atmosphere around day 27 to help the duckling break into the air space. As soon as the eggs become 'pipped', with the duckling starting to break out of the shell, the humidity should be raised to a higher level for hatching. It is essential that the eggs lose 12-15% of their weight over the incubation period. Humidity that is too high or too low will cause too little or too much weight to be lost. Water loss can be monitored by measuring loss (by weighing the eggs) or by observing the size of the air space - using a technique called 'candling' . Measuring the loss of weight is probably the better technique to use but is more troublesome to carry out and requires a reasonably accurate balance. Candling requires some skill but is more easily learnt

By removing a batch of eggs and weighing them at regular intervals, the loss in weight can be monitored and adjustments to humidity made. (It is better to measure the weight of several eggs and calculate the average loss per egg because the balance probably available is unlikely to be sufficiently accurate for small weights.) Ensure that the eggs are not excessively chilled when they are being weighed; measurements should be carried out quickly. A cloth in he scales helps prevent damage



Candling

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Candling involves holding the egg in front of a bright light in a darkened room so that the light shines through the shell. A simple way to do this is to cut a 4 cm hole in a piece of card and hold this over the bright light with the egg in front of the hole. The small cheap halogen table lamps are brilliant for the denser goose eggs.. to make even more deluxe put a piece of plywood with a hole over the lamp to view through ... careful they get hot !

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At early stages, the embryo will be seen as a dark spot, perhaps also showing the blood vessels radiating outwards(looks like a red spider!). A completely clear egg is infertile. As the egg develops, the air space at the broad end becomes larger as moisture evaporates from the egg. As the embryo becomes larger, little light will pass through the egg except to show the air space.

If it becomes apparent that the air space is too small or too large for the stage of development reached, there will have been, respectively, too little or too much evaporation of water from the egg. If the air space is too small, ventilation should be increased (and/or humidity decreased). If the air space is too large, the ventilation is too high and should be reduced (and/or humidity increased).

*Candling should be performed as quickly as possible to avoid excessive chilling of the eggs. If candling reveals that eggs are infertile or the ducklings have died, the eggs should be removed from the incubator.

HATCHING EGGS

Towards the end of the incubation period, after day 24, the eggs no longer need to be turned as the ducklings have largely completed their external development and the animal is manoeuvring itself into the correct position to make the break in the egg shell (the process called 'pipping' ...when they draw oxygen in to their lungs for the first time). Ensure that ventilation is adequate, as there is a real risk that the ducklings can be suffocated by a build up of carbon dioxide at this time.

1. Ideally, the air in the incubator should be drier on day 24, to help the ducklings break through the egg membranes into the air space. As soon as eggs are pipped, however, a high humidity is needed to stop exposed membranes from drying out, becoming tough and leathery and preventing normal hatching. In many situations, however, all eggs will not pip at the same time and so it will be impossible to provide the best conditions for both pipping and hatching. This is when a second incubator, used as a hatcher, is ideal; eggs are transferred in batches as they become pipped. Without a separate hatcher, wait until about a third of the eggs have pipped and then increase humidity. At this stage, do not keep opening the incubator to check on progress as this will allow the moist air to escape which takes some time to build up again.

2. The ducklings hatch. On day 28, though there is often some variation in development rate, the ducklings should begin to hatch. There can be a period of many hours between the first hole being made in the shell and final emergence. Only intervene if it appears that a duckling has become stuck for a period of 24 hours or more. Then it may be helpful to enlarge very carefully the hole with forceps or scissors. Keep the points of the instruments parallel to the shell and not inserted inwards or the duckling may be skewered.

Hatching can take a long time in some species; duck and turkey eggs for example can take between 36 hours and 3 days. If these species are being kept, it is important not to become impatient and help the birds along !

3. When the duckling emerges it will be wet, often blood stained and very weak. It will need at least 12 hours to dry out and it will be some time before it can stand without falling over. It should be left in the incubator or hatcher for this period and then removed to a brooder. There may be insufficient oxygen in an incubator for many ducklings to breathe and an incubator is an unsuitable enclosure in which to feed and water the young animals( and to clean up after them).

4. The yolk sac attached to the developing embryo inside the egg and is normally absorbed during the final days of incubation. Occasionally a duckling may hatch with its yolk sac hanging out. Its survival is endangered and the bird should be isolated. The yolk sac may naturally be reabsorbed but this takes time and the duckling must be kept in clean conditions to prevent infection. If, given time, reabsorption does not happen or the duckling is obviously in distress, it should be humanely destroyed as should any ducklings with other deformities or evident illness; . Any animal which is isolated and later returned to the brooder may be attacked by other birds. It works best if the animal is reintroduced at a time when food is given to all the ducklings so that attention is diverted away from the newcomer.

5. A feature of the development of the duckling is the formation of an external pouch and membranes called the allantois. Waste materials are deposited in this structure. The remains of the allantois and its wastes are sometimes seen still attached to the rear end of the hatched duckling. The remains will dry up and drop off.

6. Even with eggs set on the same day, there can be a lot of variation in the time they take to hatch and so it is important to wait at least 72 hours before discarding unhatched eggs. The remains from hatched eggs should be removed from the incubator as soon as possible and these, together with unhatched eggs, should be disposed off hygienically . The incubator should then be cleaned out and disinfected

Using a Brooder

An incubator should not be used to house ducklings, once they have hatched, rested and their feathers dried out. A brooder needs to be bought or constructed to house the ducklings and keep them warm; because of their small size, ducklings have a relatively large surface area from which to lose heat. A brooder is simply a form of enclosure with an overhead heat source.

The brooder must be sited away from draughts and placed on a large sheet of paper, preferably not newspaper.( food sacks are good) Some authorities suggest that the floor of the brooder should then be covered with a layer of good-quality wood shavings (not sawdust), available from pet shops or, more economically, in large bales from specialist suppliers (see Yellow Pages under "Sawdust and Shavings"). This, however, is not essential and does add to the mess that must routinely be cleared up.

Ducklings suffer from cramp if kept on a cold surface. Ideally they should be reared off the floor, on a wooden surface. Wherever the brooder is placed, it is wise to protect the surface by covering it with polythene or newspaper. as all waterfowl are incontinent..... and smelly

It may be necessary to cover the brooder with wire netting at some stage to prevent the birds climbing out (Muscovies appear to be relatives of apes when small). Many brooders use ordinary lamp bulbs, operating at reduced voltage, to provide a source of heat.

Lamps

1. Some means will be needed to suspend the lamp over the brooder. If using the Torne Valley lamp kit, the reflector should be suspended using the chain provided and not dangled by the flex.

An alternative, possibly cheaper, source of heat is to use an 'anglepoise' lamp. This is not designed to be used with higher wattage bulbs, so it is necessary to remove the lampshade or cover and insert at least a 60 W bulb. Check that this produces a sufficiently high temperature in the brooder, and if necessary use more than one lamp.

2. A thermometer to check the temperature in the brooder will be required; a simple room thermometer can be used for this. In the early days after hatching the ducklings must be kept very warm at about 35 °C (95 °F). As they increase in size, the temperature can be reduced by about 3 °C (5 °F) each week. ducklings will need to be given some warmth in a brooder for about 6 weeks until they have acquired their adult plumage on their chests and their wings begin to edge with feather quills .

3. Experiment with the height of the lamp above the brooder to obtain the correct temperature before adding the ducklings. The lamp should not normally be lowered so that it is within the walls of the brooder as cooking may occur. When the ducklings are installed, watch their behaviour and adjust the height of the lamp if necessary. It is normal for the ducklings to avoid the central spot immediately below the lamp but, if they move to the periphery of the enclosure and possibly also show some distress with open beaks and panting, it is evidently too hot. Huddling together tightly is a sign that ducklings are too cold

***These Tables enable you to calculate the relative humidity of your incubator at given temperatures . The wet bulb if you haven't one is a thermometer with wick or other cloth strapped around it with one end in a water supply to keep the end damp

Most Waterfowl hatch at around 48 to 555 relative humidity but this also takes into account where the incubator is kept and your area i.e.. if in a cool shed with a reasonable background humidity try the bottom end of the scale to see how the eggs progress. If indoors in a dry room the top etc.


 

المصدر: Domestic Waterfowl Club of Great Britain
Khairy4712

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