Technologies and selection methods in modern meat poultry farming

The technology of meat production from poultry is continuously developing and is implemented through the introduction of scientific and technological progress into practice. Improvements in technology reflect all changes in production factors, regardless of whether they change partially or comprehensively.

Poultry meat production technology is based on specialized rearing of young stock, characterized by high growth rate and viability, good muscle development, especially of the breast and leg muscles, and efficient feed utilization, which provides high-quality and tasty meat. Poultry meat production technology includes a number of technological processes and operations. Technological processes of meat production are regulated in relation to the biological characteristics of different poultry species based on scientific achievements and best practices to increase production efficiency and product quality.

The problem of increasing poultry productivity has always occupied the attention of zootechnicians, biologists, and physiologists. This problem is very multifaceted.

Its development is carried out taking into account the influence of a complex of biological factors — crossbreeding, nutritional level, physiological stimulation of the generative and endocrine systems of the organism by light and thermal factors, etc. At the same time, research, as a rule, is conducted in close connection with the practical tasks of improving feeding and poultry keeping systems.

Over the last two decades, fundamental changes have occurred in the development of the poultry industry. Poultry farming is developing at an accelerated pace as a large, well-mechanized industrial branch of agricultural production, the intensification of which is based on the development of specialized egg and meat-type poultry farming.

The basis for the successful development of meat-type poultry farming in our country is the application of biologically complete and high-calorie feeding and the utmost use of the heterosis effect by crossbreeding chicken breeds and lines verified for compatibility. Over the last 10—15 years, a large number of studies have been conducted in our country on the development of breeding methods in meat-type poultry farming, on the improvement and propagation of dual-purpose chicken breeds, and on testing individual chicken breeds and lines for compatibility. Thanks to this, specialized dual-purpose chicken lines have been more widely used in meat-type farms, the crossbreeding of which made it possible to obtain a large number of meat-type chicks.

The industrial production of broilers that has developed in our country in recent years, which began to outpace the capabilities of pedigree poultry farming to provide poultry farms with initial chicken stock for the production of hybrid broilers, necessitated the creation of a pool of meat-type chicken breeds for newly built poultry farms by importing broiler crosses from various countries.

Broilers are chicks of meat or dual-purpose breeds, lines, and their crossbreeds (hybrids), specially raised for meat up to 7 weeks of age. At this age, broilers should weigh at least 1.6—1.7 kg and have good meat quality and a small accumulation of subcutaneous and internal fat. In advanced specialized farms, broilers reach such weight at an even earlier age, while consuming 2.0—2.5 kg of feed units per kg of gain.

Broiler rearing is carried out in many countries with developed poultry farming. Broiler meat production in the USSR is concentrated in large specialized farms. In the first years, broiler poultry farms with a closed production cycle were built with the expectation of selling 3 million broilers per year. Recently, larger poultry farms have been built for the production of 4 and 5 million broilers per year. Projects for combines for 6, 8, and even 25 million broilers have been developed. In addition to broiler poultry farms, there are also other farms in our country for broiler production. These are poultry state farms and collective farms, as well as individual farms not specialized in poultry.

Currently, broiler farms with a closed production cycle, including a parent stock unit, a hatchery, units for rearing replacement young stock and broilers, a slaughter and a rendering plant, as well as auxiliary facilities, are not the best compared to other forms of production organization. In recent years, broiler production has been developing on the basis of cooperation between farms.

Large, highly specialized farms and individual technological links are being created, which are part of associations for poultry meat production.

The efficiency of broiler production depends primarily on the breeding qualities of the parent stock. Breeding work, even at the level of mass selection, influences not only the quantitative but also the qualitative indicators of the produced product. Experiments conducted at the Department of Poultry Science

Fig. 57. Parent stock of chickens for broiler production.

at TSHA with meat and dual-purpose chicken breeds showed that mass selection of the parent stock for meat-type precocity allows for increasing the live weight of the offspring and improving meat quality by increasing its protein content. The parent stock of broiler poultry farms serves to provide the incubation unit with hybrid eggs. They are obtained by crossbreeding compatible two, three, and four lines of paternal and maternal forms. Chicks obtained from such crossbreeding exhibit a heterosis effect in growth rate, feed conversion, and meat quality. Hybrid chicks are more resistant to diseases and more viable.

Cross breeding and incubation technology

To produce high-productivity industrial hybrids, poultry farms use two- and four-line crosses of Cornish and White Plymouth Rock breeds. When obtaining two-line poultry, Cornish roosters are mated with White Plymouth Rock hens. A four-line hybrid is obtained in two stages: first, birds from the sire and dam lines are crossed within each breed, and then the resulting two-line Cornish roosters are mated with two-line Plymouth Rock hens. Such a method allows for the assessment of the general combining ability of the lines and obtaining the maximum heterosis effect.

The productive qualities of the lines during the creation of the "Stabro-4" four-line cross are presented in the table:

For uninterrupted broiler production, the incubation department must operate year-round. For example, at enterprises with an annual volume of 3 million broilers, 25–26 settings of 14–15 thousand eggs each are carried out monthly (about 300 settings per year). Such a rhythm allows for the regular acquisition of large, uniform batches of chicks.

Day-old chicks are sorted immediately after hatching into standard and non-standard, after which primary processing of the poultry is carried out:

1. Sorting of day-old chicks into standard and non-standard.
2. Beak trimming of standard chicks to reduce the risk of injury.
3. Cauterization of spurs and claws of the inner toes in cockerels intended for replacement of the parent flock.

Broiler rearing and climate control

Industrial broiler fattening is carried out year-round using a flow system. Replacement pullets are raised mainly on deep litter in large-scale poultry houses. For floor rearing of broilers, single-story buildings are constructed, and for cage rearing, multi-story buildings (2, 3, or 4 stories) are used. Poultry houses are built from materials with good thermal insulation, which are easy to clean and disinfect. A batch of chicks is populated in one day, and at the end of the rearing cycle, the facility is completely emptied within 1–2 days to prepare for the next cycle.

Optimal feeding and housing conditions allow the full genetic potential of the hybrid poultry to be realized. The room temperature is maintained within 22–25 °C during the first days, gradually lowering it to 20 °C by the chicks' one-month age and to 16–18 °C in subsequent periods. The air exchange level is regulated by forced ventilation, adjusting it to the external air temperature within a range from 1.2–1.5 to 8–9 m³ per 1 kg of live weight of the poultry.

• Hatchability of chicks from eggs — 75–80%
• Daily weight gain of cross chicks — 25–28 g
• Temperature under the brooder in the first days — 33–35 °C
• Air humidity in the room — 60–70%
• Daytime lighting intensity — 2–4 W
• Nighttime lighting intensity — 0.6–1.8 W

Temperature regime and climate parameters

For intensive broiler rearing, it is critically important to maintain an optimal microclimate from the first days of the poultry's life. Heating of the poultry house is provided using water or air heater systems combined with electric brooders. In regions with a hot and dry climate, intake air is additionally humidified with special equipment, and the required humidity level in standard conditions is regulated by forced ventilation.

The lighting regime is set using incandescent or fluorescent lamps. If there is a threat of cannibalism, poultry houses are temporarily lit with red light. Physiologically, 24-hour lighting with controlled intensity changes for "day/night" is more justifiable than periodic full switching on and off of lamps.

Preparation of the poultry house and rearing schedule

Day-old hybrid chicks are placed in large batches of 20,000–30,000 head into a previously cleaned and disinfected facility. With floor rearing, the stocking density is from 14–18 up to 20 head per square meter. The poultry is raised without intermediate transfers and thinning until slaughter.

Before planting, the floor of the poultry house is sprinkled with slaked lime and a layer of clean, dry litter is laid down. Wood shavings, crushed corn cobs, fibrous sphagnum peat, sunflower husk, or chopped straw are used as bedding material.

• Slaked lime application rate — 0.5–1 kg/m²
• Litter layer thickness — 10–15 cm
• Litter humidity — no more than 22–24%
• Stocking density — up to 20 heads/m²
• Annual meat yield — 100–120 kg/m²

In the first days, chicks are kept within brooder enclosures so they do not scatter throughout the entire poultry house. For feeding at the initial stage, tray feeders with a metal grid are used, which are installed on special frames to protect the feed from the litter. Watering is organized using vacuum drinkers, filling them 1–2 hours before planting so the water has time to warm up.

1. 1–2 days before receiving the batch, turn on the heating to warm the air in the poultry house to 24–25 °C, and under the brooders — to 33–35 °C.
2. In the first days, keep the chicks inside the brooder enclosures with a radius of 60–70 cm, regularly changing the water in the vacuum drinkers 3–4 times a day.
3. On the 5th day, replace the tray feeders with trough feeders with a protective grid.
4. On the 7th day, remove the brooder enclosures, switch the poultry to flow-through drinkers, and begin training them to use the main technological line feeders (the transition period takes 5–7 days).
5. From the 14th–16th day, switch the chicks to automatic drinkers.
6. From the 18th–20th day, transfer the flock to automatic feeders (oscillating, chain, or belt-cable conveyors) and ensure constant access to complete compound feed.

Poultry age (days) Ingredients 1—30 SE and older Corn 54.5 68.2 Wheat 8.4 4.4 Sunflower meal 5.5 14.7 Peanut meal 11.9 — Fish meal 71.2 2.9 Meat and bone meal — 2.0 Feed yeast 5.0 3.2 Dried skimmed milk 30 — Grass meal 3.0 3.0 Chalk 0.5 0.6 Premixes 1.0 1.0 Total 100.0 100.0 100 g of compound feed contains (%): metabolizable energy, kJ 1239 1302 crude protein 21 19 crude fiber 5.0 5.0 calcium 1.0 0.8 phosphorus 0.8 0.8 sodium 0.3 0.3 lysine 1.05 0.95 methionine -- cystine 0.74 0.65 tryptophan 0.20 0.18 Energy-protein ratio 590 685 (kJ: crude protein)

A high level of automation and mechanization makes it possible to increase the workload for the operating personnel. At modern broiler farms, one poultry operator manages 3—4 poultry houses (60—80 thousand chicks), but with such a high load, it is necessary to strictly observe the daily routine.

9* 243 Table 48. Feeding and watering space for broiler chicks

Chick age (days) Feeding space (cm) Watering space (cm) 1-14 25 1.0 15—28 5.0 1.5 29—63 8.0 2.0

Raising broilers in cages. The expansion of poultry meat production volumes at specialized poultry farms makes the search for ways to use premises more rationally and to create conditions for the mechanization and automation of poultry care processes a matter of particular urgency. Cage rearing of broilers, compared to floor rearing, allows for housing 3—4 times more poultry in the same production areas. Furthermore, in cages, it is much easier to create optimal veterinary, sanitary, and zootechnical conditions for broilers.

There is an opinion that when keeping broilers in cages, the commercial quality of the carcass deteriorates due to the appearance of so-called bruises (accumulation of exudate under the skin in the area of the front edge of the keel of the breastbone). However, this can only happen if the growing period lasts more than 10 weeks. Currently, when broiler growing periods have been reduced to 49 days, the formation of bruises is practically not observed. The meat (especially breast muscles) of chicks raised in cages is characterized by a higher protein content and a lower percentage of moisture.

In cages, the danger of poultry infection with coccidiosis and other diseases spreading through manure is reduced. There is absolutely no need for litter material. Broilers are placed in cages in small groups, which facilitates zootechnical and veterinary service. Due to the fact that poultry movement is limited in cages, energy expenditure is reduced, resulting in a decrease in feed consumption per 1 kg of gain. Moreover, when raising broilers in cage-containers, such labor-intensive operations as catching the birds before slaughter, cleaning the premises, etc., are eliminated. All this allows cage rearing of broilers to be considered promising.

Broilers are most often kept in battery cages of the KBM-2, KBU-3 types, as well as in single-tier BGO-140 and R-15 units. Although these cages are not designed for raising broilers, they can be fully adapted for this purpose.

Broilers can be raised in any facility where battery cages can be properly installed. In this case, the poultry house floor is constructed to ensure good water drainage into sewer channels. The facility is equipped with forced ventilation and air heating systems. To create a uniform temperature regime across all rows and tiers of the battery cages, special pipes are laid along the aisles near the cages at a height of 10—15 cm from the floor.

In the first days of raising chicks in battery cages of the KBU-3 type, it is necessary to place sheet rubber or polyethylene overlays on the floor mesh so that the chicks do not fall through and get injured. These overlays are used for 10—15 days, then they are removed from the cages, washed, disinfected, and stored until the next batch of chicks is placed. In addition to overlays, thick paper can be used, which is burned after use.

In battery cages equipped with nipple drinkers, it is necessary to additionally install trough or self-cleaning micro-cup constant-level drinkers during the first days of raising, since chicks cannot find nipple drinkers in the first days of life, resulting in increased mortality. To help chicks find the drinkers faster, it is advisable to paint them red. To avoid the formation of breast blisters, the cage floor mesh should be covered with polyethylene or soft mats with round holes 25 mm in diameter should be used.

When stocking cages with day-old chicks, special attention should be paid to their uniformity and leg strength. Uniform, sex-separated chicks that stand firmly on their legs grow significantly better and develop far fewer breast blisters. The other criteria used for selecting day-old chicks are the same as for floor rearing.

The arrangement of feeders and drinkers when raising broilers in cages should ensure free access to feed and water for the poultry both at the beginning and at the end of the raising period. In the first days of raising, special inserts are placed in the feeders so that the chicks can better reach the feed. For the chicks' well-being, it is necessary to create an optimal microclimate in all tiers of the cages, as they are deprived of the ability to move and choose zones with the appropriate temperature. Therefore, the maintenance of a specific age-differentiated temperature regime in all tiers of the cages is strictly monitored.

Table 49. Differentiation of the temperature regime when raising broilers in cages

Air temperature (°C) Age of chicks (days) in the cage in the room 1—7 32—30 30—28 8—14 30—28 27—25 15—21 21—25 22—20 22—28 24—22 20—18 29—42 21—20 18—16 43—49 20—18 15—14 50—56 18—16 14—13

Relative humidity in the poultry house is maintained within 60—70%. An increase or decrease in humidity negatively affects the heat exchange and heat dissipation processes in chicks. With an increase in air humidity (above 80%) and high temperature, respiration becomes difficult for chicks, they become lethargic and lose their appetite, while at low humidity, the plumage becomes dry and brittle, and the chicks eat little and drink a lot of water.

When raising broilers in cages, it is especially important to monitor air exchange in the poultry house, as the concentration of livestock increases, and consequently, the amount of harmful gases emitted by the birds rises. Compliance with the air regime is possible only with the use of forced supply and exhaust ventilation. Normal air exchange is achieved by supplying the following amount of fresh air per 1 kg of broiler live weight per hour: 1.8—2.5 m3 in winter, 7—10 m3 in summer, and 3—6 m3 in spring and autumn.