How to Rear Parent Flocks for Peak Production

How to Rear Parent Flocks for Peak Production

Broiler breeds such as the Cobb500 are selected to efficiently convert feed to body weight. Therefore, it is important in rearing parent flocks to understand how to feed the birds correctly right up to peak hatching egg production.

Phase 1: Day 1 to 4 weeks of age

This is a very critical period for development of organs and physiological systems, including the immune system, and requires optimal brooding conditions. Regardless of the feed type and feeding program used, achieving the standard body weight through the weekly target weight increment is a top priority. So too, is a good vaccination program, providing protection against prevalent field viruses (mainly respiratory), bacteria (mainly Mycoplasmas, Salmonella and E-Coli) and parasites (mainly Coccidia).

However, biosecurity can be more important; the most successful facilities in disease prone areas or during an outbreak are those who use two showers in and a shower out system—in addition to complete clothing and boot changes.

Phase 2: Week 5 to week 12

This phase is known as the uniformity correction period. This can be achieved and maintained through careful feed intake and body weight management. Birds should be selected individually between the 3rd and 4th week and regrouped into target weight, underweight and overweight categories. Birds will then have

equal access to feed and water to grow homogeneously. The birds should not be disturbed by daily or biweekly selection unless the uniformity is <80%.

This is the only chance to correct the average body weight of the flock until 12 weeks of age where 95% of their skeletal development is completed. For the heavy group, the minimum weekly feed increment/ hen should be 1 gram – never reduce the feed intake. For the underweight group, a maximum of 10% over feed increment/ week/hen can be administered; otherwise, birds can get obese with a small frame causing mating problems with males in the laying period.

Minimum feeding space should be 10 cm/hen for chain and no more than 13 females/35 cm diameter round pan. We are limited in our ability to correct over/under feeding issues after 12 weeks of age.

Phase 3: Week 12 to Week 16

The main target is to retain good uniformity of body weight and frame, and to ensure hormonal development without fleshing. By now 95% of skeletal development is achieved, so there is no way to correct frame size further. Regrouping the homogenous birds together gives birds with similar weights and frames an equal chance for feed intake and allows them to maintain a good uniformity, leading to maximum egg production in the laying period. Hormonal development will need minimal, but good quality nutrient intake.

We follow a conservative feeding regimen with a +/- 3 grams weekly feed increment/hen depending on feed density, season, health status and vaccination program. Feed space per hen should not be <15 cm on chain and no more than 12 hens per round pan feeder. Birds should be kept tranquil to avoid any mechanical injuries or feather licking, which can lead to pecking. Provide 5 lux of cool white light (3000 Kelvin). Introducing perches will help hens become familiar with the laying nests before entering the laying house. This also increases the floor space.

Phase 4: Week 16 to week 20

This is the most important period in preparing hens for maximum egg production. The hen needs to acquire the necessary body reserves for the onset of laying. This depends on the glycoprotein accumulated inside the reserves and not on the excess energy provided by higher feed intake. We should increase the fleshing of the breast of the hens (score 3), as well as the fat deposition measured on the pelvic bones and under the wing (score 3). The best performing flocks showed an increased body weight by no less than 33-35% during this period.

Feed Increment should be enough to ensure a body weight profile parallel or better than the standard curve. Feed regimen should be back to daily feeding at 16-17 weeks of age, which helps maintain a homogenous flock. Selecting or regrouping the birds with similar body weight and frame will help the mixing of hens with the males and also light stimulation timing – the most important decision in a hen’s life.

Phase 5: 21 weeks to peak production

Transfer the small birds from all rearing houses to one house and treat them as a younger homogenous flock, delaying light stimulus until they are sexually matured with enough body reserves. The overweight birds can be transferred to one house and given four hours of additional Light at 147 days of age. The best performing flocks in the Middle East area have light stimulation at 154-157 days old and 15 hours of light in laying period, but 14 hours can be sufficient.

Mixing males with females should only be done if both are sexually synchronized. This can be at 22 weeks, introducing the first 5% of the males followed by the next 2%, and then another 2% in 3- 5 days, which helps acceptance by the hens. If males are aggressive, wait one week and re-assess. We do not want a scenario of non-sexually mature hens running away from males, causing infertile eggs. At peak production, 8.5% males can fertilize all the females.

Feeding hens should be conservative until onset of lay. Administering extra energy for the birds to force egg production will only lead to over fleshing and fat deposition and higher hen mortality due to erratic oviposition, prolapse, peritonitis, fatty liver and sudden death cases. Although the regular feed increment is based on egg production numbers, the top performing flocks were fed conservatively, with 4 grams weekly feed increment until 30% hen day egg production. Then higher feed allocations can be given (10 grams/hen/week) to reach peak/ feed (165 grams/bird/day) at 70-75% production.

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