|By goGreen | November 22, 2011|
6.1 What should have been done before breeding starts?
At the end of the growing period of the breeders the following matters should have received attention already. When the production of hatching eggs has started, it is too late for these measures:
- vaccination schedules for breeder birds are different from commercial egg laying birds
- blood titers should have been checked
2. debeaking; female breeders should have been debeaked
3 6-8 week selection; in meat-type birds the smaller males and females are removed at this stage
4 mature selection; just prior to the onset of egg production, males and females of poor quality are removed from the flock
5 if sexing errors are discovered, remove the birds concerned immediately, at any time
6 internal parasites; if worms were present during the growing period, an effective eradication programme should have been carried out – allowing the birds to start their breeding period free of worms
7 Mg, Ms and Pullorum negative; just before or immediately after egg production starts, the cockerels and the hens should be bloodtested
8 correct mature body weight
- the feeding programme during the growing period should have been such that it produced a specified body weight at sexual maturity
Again, the above should have been done or accomplished during the growing period. REMEMBER: ONE CAN HURT, BUT NO LONGER HELP A 21-WEEK OLD CHICKEN!
6.2 The importance of correct body weight
Breeder birds should have the right body weight when they reach sexual maturity; therefore they should be weighed, at least every two weeks. In particular, medium size and meat-type birds have a tendency to develop too much body fat. For these types the body weight should also be controlled during the period of egg production.
Good body fleshing but without excessive fat is desirable for the following reasons:
- onset of egg production is delayed
- first eggs are larger
- egg production during the laying cycle is increased
- more hatching eggs are produced (because the eggs will be of a larger size)
- laying house mortality is reduced
- feed cost of growing pullet to sexual maturity is lowered
- feed cost of producing a hatching egg is reduced
- fertility of the hatching egg is increased
- hatchability of the hatching egg is improved
If the breeder birds are fed to appetite during their growing period, they may be too heavy at sexual maturity and may not produce the possible maximum number of eggs during the laying cycle.
Feed allocations should be made with the aim of obtaining the recommended body weight for the particular type of bird concerned. There are no set rules: follow the instructions of the breeder of the birds.
To check the body weight, females should be weighed once every two to four weeks during the laying cycle. Weigh a representative sample of the hens in each pen. Weigh a sample of the males too.
6.3 Measures to improve fertility
About 4 weeks before reaching sexual maturity (i.e. at about 18 weeks of age), the males should be placed with the females. Do this late in the afternoon, as this will reduce fighting; fighting will occur for about half an hour in this case, until sunset (the next morning it is over).
Too many males in the breeding pen reduces fertility; not enough males has the same effect. The ratio is about 1:10; slight deviations may be useful depending on the breeds involved, as is shown in the following table (indicative only).
A few extra males should be placed in the pens at the time when the cockerels are introduced to the hens, to allow for some early culling and mortality from fighting. But remove them as soon as the flock seems to have come to rest.
- Males mate between 20-80 times a day. During hot weather cocks have a reduced sex drive, which may result in no significant fertilization of eggs at all. Most matings take place in the cooler part of the day (early morning).
- Fertile eggs will be produced for days after the males are removed from the flock; but if males are removed and new males added to the flock the same day, the fertile eggs produced after three days will be the result of matings by the new males.
- Excessive body weight of the male at maturity must be avoided.
- Any inferior looking male should immediately be removed (catch by both legs).
- Exercise the males: strew a little grain in the litter, several times a day.
- Use proper equipment for the males. Often feeders and drinkers are inadequate for cocks. Place special feeders for cocks if their body weight is too low. Place them higher so that only the cocks can reach them.
- The timid male. In males as in females there is a certain social order. A timid male may not receive enough feed. Make sure that there is enough feeding space.
- When cocks have sore feet they will not mate. Treat immediately.
- Males not mating. On a partly litter floor, males will show a tendency to remain on the wire/slats, as a sort of ‘roosting’ place. Hens prefer to be mated on the littered part. Strewing a little grain in the litter will cause the males to come down.
- Age of breeders: cockerels (young males) give better results than older cocks. It is not advisable to use males above two years of age.
Light during the egg production period stimulates the production of eggs and also increases the quantity and the quality of the semen of the males. Apply a specified lighting schedule.
6.4 Hatching egg production
The only purpose of keeping breeding birds is to produce an abundance of hatching eggs that will give a high percentage of quality chicks. The following management practices are important for the production of hatching eggs:
Hatching eggs are valuable and egg breakage is costly. Therefore abundant nesting material should always be available. It should have the following properties: absorbent, durable, coarse so that it will not easily be blown from the nest, dust free, good cushioning quality and inexpensive. Useful nesting materials are wood shavings, groundnut hulls, rice husks, chopped corn cobs, straw and hay.
The breeder hens should be trained to use the nest rather than the floor on which a high percentage of the eggs laid will be broken. Floor eggs are also less suitable for hatching. To induce hens to lay their eggs in the nests:
- place the nests in the pen before the birds start laying
- put the nesting material in the nests at the time the nests are placed; keep the nesting material clean before egg production starts
- if roll-away nests are used, put nesting material in them before and during early egg production; hens refuse wire-floored nests
- provide adequate nesting material; if the material has been blown out of the nests, or if it is wornout, with bare surfaces showing, the hens are not likely to lay eggs in the nests
- block off corners of the pen where hens congregate and are likely to lay eggs on the floor; do this before egg production starts
- make sure that there are enough nests; if a hen cannot find a nest in which to lay an egg, she will be forced to find a ‘nest’ on the floor
- disperse broody hens as they take up nesting space, forcing other hens to lay eggs on the floor
Collecting hatching eggs
Hatching eggs should be collected from the nests at least 4 times per day; in extreme temperatures 5-6 times per day. Frequent collection decreases breakage and helps to maintain the hatching potential. It is important to collect the eggs that are laid late in the afternoon on the same day. Hatching eggs left in the nest overnight will lose some of their hatching qualities.
Suggested time schedule for the collection of hatching eggs, under a natural daylight programme:
- 3 hours after sunrise (e.g. 09.00 hrs)
- 4 hours after sunrise (e.g. 10.00 hrs)
- 5 hours after sunrise (e.g. 11.00 hrs)
- 6 hours after sunrise (e.g. 12.00 hrs)
- 7 hours after sunrise (e.g. 13.00 hrs)
- 11 hours after sunrise (e.g. 17.00 hrs)
Close the nests at night and open them again early in the morning, before egg production starts. Do not allow hens to sit in the nests overnight and remove any hen found in the nests, to prevent broodiness.
- use only plastic egg flats (key-trays)
- never use a bucket or basket because eggs piled on top of each other will break and cannot cool down
- place the eggs with the narrow end down
- when collecting eggs, separate the extra large/double yolk/misformed & cracked eggs from the normal ones
- do not carry more than 2 egg flats on top of each other unless a special carrying device is used
- disinfect and fumigate egg flats after use
The hatching eggs should be fumigated as soon as possible after collection. Storage time should be as short as possible. At 2-3 days after laying hatchability decreases. For short periods (up to 4 days) hatching eggs should be stored at 18-20 °C. For longer storage periods, the eggs should be stored at 18 to 14 °C; longer than ten days at 12 °C. Try to maintain a relative humidity of 80% or more.
Selection of hatching eggs
Hatching eggs should be first-class, fertilized eggs. There is no way yet of checking the fertility before incubation, but the practices outlined below will help to eliminate possible failures.
- do not include dirty floor eggs
- only first class eggs should be used; all eggs with obvious abnormalities should be rejected
- misformed eggs do not hatch well
- broken or cracked eggs are useless because they dry out inside the incubator
- small eggs usually give weak chicks
- long eggs are mostly ‘double yolks’ which will never hatch
- abnormally coloured eggs are usually the result of a genetic defect.
There are specific egg-weights for each type of chicken according to their production season, but in general a hatching egg should weigh between 52 and 70 g. Handle hatching eggs carefully because they are costly!
REMEMBER: ANY DIRTY OR CRACKED EGG IS LOST AS A HATCHING EGG.
Breeding birds should produce parental immunity in chicks. To produce a constant degree of parental immunity it is necessary to revaccinate the breeder females for Newcastle Disease and Infectious Bronchitis at intervals of 12 weeks during the laying period. See Chapter 8 ‘infectious disease and their prevention’.
6.5 Guidelines for the selection of breeding stock
The selection of males and females for future breeding stock should be based on the relative economic importance of each characteristic that is considered in the selection process. Every hen selected for breeding purposes should be carefully examined.
The following is a list of desirable characteristics:
- good breed type
- reasonably good plumage colour
- free from defects
2 egg production
- early sexual maturity 82 The basics of chicken farming (in the tropics)
- high rate of laying
- no pauses (or only short ones) in egg laying
- persistence of production
3 egg quality
- standard egg size
- proper shape and colour
- uniform shell texture
- high % of thick albumen
- no blood spots etc.
The above characteristics can most easily be checked by trapnesting the birds. An individual check for each bird will give information. Trapnesting for 3 consecutive days per week gives enough information. The other 3 days can be used for trapnesting another flock or for doing any other job. This will save time and labour. Trapnesting is usually done over a period of 300 days. Checks every 4 weeks and individual hen recording will give sufficient information.
- high fertility
- high hatchability
- quality chicks
Incubation and hatching records will give information.
5 viability of growing stock and layers
- low mortality %
- low culling %
Any bird still present at the age of 12-15 months will have a rather high resistance to diseases and/or other unfavourable conditions. The collection of eggs for future breeding stock should therefore not start before this age.
6 meat production
- rapid growth
- early feathering
- superior breast fleshing
- good body size
Body weight at 6-8 weeks of age gives a good indication of the weight of the offspring later on. There is little correlation between body weight at sexual maturity and the weight of the offspring. Selected birds (at 6-8 weeks) should be checked at marketing time (9-14 weeks) on the following characteristics:
- feathering; full feathering is desired (pin feathers lead to discount in price when the birds are sold)
- breast fleshing
- body size
Each of the above characteristics has to be taken into consideration on the basis of its relative economic importance. For instance, selection on (a) has hardly any economic value and (f) is only important for meat-type breeders. Note: the selection on feed consumption and conversion should be taken into consideration too, but these are very difficult to measure on the individual bird.
6.6 Recycling of the breeder flock
Breeder flocks used for the production of hatching eggs are often force-moulted and ‘recycled’. The reasons for doing this are:
- to supplement normal hatching egg production
- to compensate for high mortality in the growers; if there is excessive mortality in the growing flock that is going to replace the present flock, the latter may assist a second time in the production of hatching eggs
- an unexpected heavy demand for chicks (the demand for day-old chicks is sometimes difficult to predict)
- for single-line breeders, recycling the flock (or part of the flock) is the most reliable method of improving the breed
Force-moulting can be achieved by one (or a combination) of the following methods:
1 Water withdrawal for one or two days, after which water supply is restored and then withdrawn for another two days. Not to be practised during hot weather.
2 Feed withdrawal for several days, or feeding an unbalanced ration (feed grains only).
3 Light withdrawal in environmentally controlled houses, well below 11-12 hours per day.
Any one (or a combination) of these methods will create stress in the birds, causing them to drop their feathers and lose weight. Hopefully not many of them will die.
After two days of depriving the birds of water and/or feed, a return is made to a skip-a-day programme (one day feed, the other day water) which is continued for one week. After this a normal, controlled (restricted) feeding programme. After 60 days the light may be stepped up to 14-16 hours per day. Egg laying will resume.
Force-moulting a flock and recycling is only worthwhile if the quality of the flock is excellent. Only birds having desirable characteristics should be used.
In most cases it is advisable to add new males to the breeder flock because they are more fertile.
Note: it should be kept in mind that force-moulting is a difficult technique and it should not be taken lightly. In a tropical climate moulting can quite easily take place accidentally too! For instance because of a heat stroke, watering failure or a sudden change in feed quality. Accidental moulting always means a very serious economic loss.
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