In reality, 90% weight uniformity is achievable with grading and feeding management.

Broiler breeder management is complicated, and without due attention, one cannot expect consistent flock performance. Rearing broiler breeders should be considered a long term process, and which does not end with the transfer to laying facilities.

The first 10 days after placement is the most critical time for the flock, as there is a direct relationship with how birds perform during lay. Continued selection has produced a breeder pullet that grows faster and deposits breast meat more readily on less feed. However, the basics of pullet rearing have not changed.

The best start 

A major requirement for successful early chick development is that there be only a minimal environmental challenge. Buildings must be washed and disinfected following clean out of litter, and be fumigated. The water line must be flushed, disinfected and sanitized, followed by a final flushing with clean water.

Brooding remains critical to developing a good, uniform flock. The development of the immune system, the skeleton and feathers are highly dependent on body weight development and, because they are important for future performance, the aim of brooding is, therefore, to attain optimum growth.

While temperature is a major factor for management over the first 10 days, adequate air movement is also needed to maintain the balance of oxygen, carbon dioxide and moisture. It is important that incoming air is well mixed with the ambient air.

Litter temperatures of 90F (32C) at day 1 and stepping down to 75F by 4 weeks is adequate. Make sure that floor material is comfortable for chicks. With their body temperature of 105F, chicks will be chilled if litter is too cold, and cold chicks do not go to feed and water. When chicks first arrive, their immediate need is usually water, rather than feed. Clean water, ideally at 20C with, or without, electrolytes and antibiotics, should be provided for 3-4 hours before introducing feed.

Early growth 

If full feeding during the first 2-3 weeks is considered, the length of time that starter feed is used will vary according to chick weight. The period will need to be longer if underweight and shorter if overweight. The same applies for the lighting.

Light intensity of 60 lux during the first three days will allow chicks to become familiar with their surroundings. Stocking density at placement should allow all birds to access feed and water at the same time - place only 25 chicks per square meter. Management during brooding must result in the best possible uniformity before feed restriction starts.

Males 

The first 4 weeks of the breeder male’s life will dictate its frame size at maturity. Without adequate size, the male will have difficulty in carrying necessary body weight and mating. Male breeder chicks need more light during the starting period to facilitate early growth and achieve targeted frame growth, as both these factors have a positive co-relationship with fertility.

The development of frame size depends upon feed and protein consumption. The starter feed should have at least 18% crude protein, and should be given for at least 28 days or until chicks reach 650 grams.

For breeder male chicks it is better to be heavier at 4 weeks. Depending upon the amount and nutrient density of starter feed, adjustment of the light period is required to give adequate time to consume enough feed to reach the desired body weight.

Pullet phase needs constant observation 

The main criteria used in assessing the progress of pullets are the average flock body weight and uniformity. In reality, 90% weight uniformity is achievable with grading and feeding management, however, 80-85% uniformity is standard.

Uniformity of 75-80% is needed from 4-20 weeks. To avoid penalising lighter birds during the severe feed restriction period, a general grading is often recommended at 28 days. If significant differences are reported, pens of small, medium and large birds are created and fed according to weight. The earlier grading is conducted the better.

Competition and stress increase as the flock reaches its peak, primarily during 8-16 weeks. Body weight and fleshing need to be controlled from 15–20 weeks. It is better to avoid using high density pre-breeder diets too early as this promotes excessive fleshing. Associated with fleshing is the need for a minimum fat content in the body.

In principle, the objective behind pullet management is to achieve ideal body weight, fatness and fleshing and to obtain uniform growth coupled with hypothalamic maturity by following a restricted, but gradually increasing, feeding program and managing the environment in order to prepare the birds for sexual maturity.

Shank and keel length can also be monitored as a means of assessing pullet development, as they are correlated to body weight, meaning that, underweight birds have shorter shank and keel lengths. The opposite is true with overweight birds, especially up to 16 weeks.

While feeding females during the growing period, the basic objective is to restrict their calorie intake to produce leaner pullets that are older when they lay their first eggs. Breeders should not be fat, but must be conditioned and fleshy enough to become sexually mature with increased lighting.

Pre-layer management 

The period from 115 days to light stimulation is key in the onset of egg production, early egg size, and hatching egg yield.

Minimizing variation in sexual maturity and preparing females for the physiological demands of sexual maturity, and ensuring that males develop optimal physical condition and are able to sustain reproductive fitness, are among the objectives of pre-layer management.

From the egg production point of view, it is beneficial for birds to be slightly heavier. However, focusing on body weight alone is ineffective as pullet weight alone is a crude indicator of subsequent performance. And birds must have at least the minimum amount of muscle at light stimulation, as body weight at lighting is correlated with egg production.

But, the core factor influencing performance is nutrient intake and not body weight. Pullets at this age should present ideal carcass composition and have an optimal number of large ovarian follicles. With reproductive development, ovarian hormones play a major role in the changes in ingestion, partitioning, and utilization of metabolic energy.