Vai alla Home Page About me Courseware Federica Living Library Federica Federica Podstudio Virtual Campus 3D Le Miniguide all'orientamento Gli eBook di Federica La Corte in Rete
 
 
Il Corso Le lezioni del Corso La Cattedra
 
Materiali di approfondimento Risorse Web Il Podcast di questa lezione

Fernando Grasso » 13.Chickens


Farming systems

Chicken housing systems
There are basically three systems from which the farmer can choose:

Extensive
This system of keeping chickens is the oldest form of keeping chickens. According to this system, chickens are not provided with any housing, feed and medicine. Chickens can walk all over the property feeding themselves, laying their eggs anywhere, hatching and rearing chickens. With this system there is no control over the number of eggs that can be collected, or the number of chickens that are hatched, and grow up.

Semi-intensive
When using this system, the chickens are provided with housing, nests, feed and medicine. There is also a outdoor run attached to the house where the chickens can walk freely. By providing them with housing and nests, there is control over the number of eggs as well as the number of chickens that are hatched and grow up.

Intensive
In this system the chickens are kept inside an house and are provided with feed and medicine. Normally this system is for commercial use only.

Farming systems

Intensive chicken farming

Egg production is one of the most intensive forms of farming, and laying hens can produce around 300 eggs each per year. Each hen is usually kept one year for the production of eggs. In egg-producing farms, birds are typically housed in rows of battery cages. Environmental conditions are automatically controlled, including light duration, which mimics summer daylength. This stimulates the birds to continue to lay eggs all year round. In egg-producing farms, cages allow for more birds per unit area, and this allows for greater productivity and lower space and food costs, with more efforts put into egg-laying. The cage environment of egg producing does not permit birds to roam. The closeness of chickens to one another frequently causes cannibalism. Cannibalism is controlled by debeaking (removing a portion of the bird’s beak with a hot blade so the bird cannot effectively peck). Another condition that can occur in prolific egg laying breeds is osteoporosis. This is caused from year-round rather than seasonal egg production, and results in chickens whose legs cannot support them and so can no longer walk. During egg production, large amounts of calcium are transferred from bones to create eggshell. Although dietary calcium levels are adequate, absorption of dietary calcium is not always sufficient, given the intensity of production, to fully replenish bone calcium.

Layout of the battery cages.

Layout of the battery cages.

Battery cages used in intensive farming for egg production.

Battery cages used in intensive farming for egg production.


Farming systems

The advantages of cage system are:

  • greater number of laying hens is reared per unit of area;
  • production of clean eggs;
  • feed efficiency and egg weight are better in caged birds than the laying flock under deep litter system;
  • control of vices of poultry cannibalism and egg eating;
  • easy control of parasitic disease like coccidiosis and worm infestation.

The disadvantages are:

  • difficulties in ensuring proper ventilation to birds especially in summer season and under very high densities;
  • conditions;
  • incidence of leg problem, cage layer fatigue, fatty liver syndrome, flies and obnoxious gases in the house will be on the increases;
  • hysteriosis of chicks.

Farming systems

Hens naturally like to build and search for nests, and they prefer a quiet and dark place to lay their eggs. This is often not possible in battery cages, and as a result, the hens can become frustrated. Therefore, battery cages are due to be banned in the European Union from January 2012 after a 10-year phaseout, to be replaced by enriched cages.
Enriched cages are required to provide:

  • at least 750 cm2 of cage area per hen, 600 cm2 which shall be usable (usable area is defined as, other than any nesting area, used by laying hens at least 30 cm wide, with a floor slope not exceeding 14% and with headroom of at least 45 cm) the height of the cage other than that above the usable area, shall be at least 20 cm at every point and no cage will have a total area of less than 2,000 cm2
  • a nest litter such that scratching and pecking are possible (a dust bath);
  • appropriate perches at least 15 cm per hen;
  • suitable claw shortening devises.

The EU has rules to improve the wellbeing of laying hens. For example, hens must be kept in a certain amount of light and a certain amount of darkness every day, to give them the impression of day and night. Furthermore, the birds must have some opportunity to move and be provided with the minerals necessary to produce eggs and stay healthy.
Battery cages that will be banned from January 2012.

Battery cages that will be banned from January 2012.

Battery cages that will be banned from January 2012.

An example of an enriched cage.
From: Big Dutchman.

An example of an enriched cage. From: Big Dutchman.


Farming systems

Description of the different areas in an enriched cage.
From: G. Salza, Servizio Produzioni Agro-Alimentari e Relazioni di Mercato, Regione Emilia-Romagna.

Description of the different areas in an enriched cage. From: G. Salza, Servizio Produzioni Agro-Alimentari e Relazioni di Mercato, Regione Emilia-Romagna.


Farming systems

Free range farming

The majority of poultry are raised using intensive farming techniques. One alternative to intensive poultry farming is free range farming.
Opponents of intensive farming argue that it harms the environment and creates health risks, as well as abusing the animals themselves.
Advocates of intensive farming say that their highly efficient systems save land and food resources due to increased productivity, stating that the animals are looked after in state-of-the-art environmentally controlled facilities.
Free range poultry farming consists of poultry permitted to roam freely instead of being contained in any manner. A free range chicken must have daytime access to open-air runs during at least half of their life.

Free range is the poultry housing system most actively supported by welfare groups for egg production. Free range hens are free to roam during daylight hours but are secured at night as protection from inclement weather and predators. Feed and drinking water points are available within the shed housing which is in accordance with bio-security regulations.

Farming systems

Barn
Barn hens are housed on deep litter in secure and weatherproof sheds. While they are provided with ample water, feed, ventilation, space and nesting boxes, they do not range out of doors.
Limited stocking density allows room for the opportunity to express their full range of natural behaviors. They have the freedom to flap their wings, stretch, fly and dust bathe. This allows hens to move around and explore their environment.
The extra space also allows submissive birds to avoid dominant birds if they need to, which can reduce aggressive pecking and improve welfare.
Hens have access to a private, enclosed area for laying, which is a priority for hens. Beak trimming is generally allowed with most bird’s beak trimmed at one day old to limit feather pecking and cannibalism.
Barn sheds are usually fully automated with central nesting boxes over conveyor belts which carry the eggs out of the shed into a packing area, thus avoiding human contact.

Layout of a hen barn. From: INSAVI Equip. Avícolas S.L.

Layout of a hen barn. From: INSAVI Equip. Avícolas S.L.


Farming systems

Organic egg production
Only free range hens can be used to produce certified organic eggs and must be grown without the use of artificial colours and synthetic chemicals, according to the national standards.
Animals are fed certified organic feed grown from soil that is certified as organic and does not contain pesticides or inorganic fertilisers.
Under the regulations, no antibiotic medication is to be used for treatment of organic poultry.
Organic standards for egg production specify the types of feed, accommodation, and living conditions which are suitable for organic laying hens. While healthy hens require shelter for security and protection against the elements, they also benefit from the freedom to scratch and forage naturally outdoors. A clean, pollution-free range provides a suitably varied natural diet, one that is rich in essential vitamins, minerals, and trace elements.

Hens reared in an organic system.

Hens reared in an organic system.


Farming systems

Poultry meat farming
Meat chickens are not housed in cages. Most broiler chickens are conventionally reared indoors in large poultry houses, on a bedding of chopped straw or wood shavings called litter.
After hatching, chicks are removed from the incubator, dried off, cleaned, and placed in a warm dry environment.
The chicks are sexed and separated into groups.
At one day of age chicks are vaccinated and the beaks are trimmed to prevent canabalism.
Conventional indoor systems provide chickens with nutritious feed and clean water and have fan ventilation to maintain fresh air for the birds.
The number of chickens in each house depends on the floor area and the ventilation capacity and feeding and drinking facilities in the house. Most conventional houses have around 20,000 chickens but some very large houses accommodate flocks of 40,000 birds.
The chickens have adequate lighting to see by and to find feed and water, with some periods of darkness each day to allow them to rest and to avoid panic in the event of a blackout.
The lighting provided is usually dimmer than natural lighting, as dimmer lighting tends to promote calmness in flocks of meat chickens.

Broiler house. From: D.L. Cunningham, University of Georgia Cooperative Extension Bulletin 1228.

Broiler house. From: D.L. Cunningham, University of Georgia Cooperative Extension Bulletin 1228.

Feeding and drinking equipment utilized in a broiler house. From: Falcon S.r.l.

Feeding and drinking equipment utilized in a broiler house. From: Falcon S.r.l.


Farming systems

Chickens are generally robust creatures but their health and welfare must be considered and protected in any farming system. Therefore, in the case of intensive farming system, the stockman always pays close attention to a number of factors which include:

  • feed and water: providing a healthy diet including cereals such as wheat and maize, added vitamins and minerals and constant access to fresh, clean water;
  • temperature: maintaining a reasonably constant temperature for the birds’ comfort; chickens are sensitive to extreme temperatures when combined with high humidity and can die from overheating;
  • air quality: managing ventilation in the house to prevent build-up of carbon dioxide, ammonia, and dust produced by the birds, and avoid breathing problems for the chickens;
  • litter quality: maintaining the litter in a dry and friable condition; wet litter can cause skin problems for the chickens and will affect the quality of the air; however, the litter should be not too dry to avoid dust problems in the house;
  • space: ensuring chickens have space to move and exercise, in order to be able to eat and drink and to develop bone and leg strength
  • careful handling: treating and handling birds carefully to reduce stress and prevent injury; stockmen working on chicken farms are usually well trained and know how to handle and catch the animals, as well as how to check them for any problems.

Chickens have to be inspected at least twice a day.

Farming systems

Other types of farming provide more space inside or allow the birds to go outside. These other farming types are defined in EU marketing regulations and indicated on the labels of the chicken products in the supermarkets as:

  • free range broiler chickens are from systems which allow birds’ access to the outdoors; there are slightly different conditions laid down for different free-range labels; free-range broiler chickens have continuous day time access to open-air runs mainly covered by vegetation during at least half of their lifetime; they grow for eight weeks to reach market weight;
  • traditional free range broiler chickens are raised in small flocks; each chicken has twice the area outdoors compared with free range chicken; from at least six weeks old the chickens have continuous day-time access to open air runs; they grow more slowly taking over eleven weeks to reach market weight;
  • organic chickens are kept in a similar system as the traditional free range chickens, but have two additional requirements:
  • feed must be predominantly from certified organic ingredients
  • animals cannot be treated with routine vaccination; there are exceptions, such as where treatment is required by law or disease cannot be controlled with organic management practices.
Broilers reared in free range system.

Broilers reared in free range system.

Broilers reared in organic system.

Broilers reared in organic system.


Breeding

The life of a chicken raised for meat starts at the breeder farm. The hatchings become the great-grandparent flock, which produce grandparent stock, which in turn produce parent stock – it is the offspring of the parent stock that are raised for meat production. The synchronised hatching of commercial chickens is important to ensure they are all the same size and reach maturity together. This is achieved by having uniform incubation conditions for egg hatching. Meat chickens today can reach a weight of approximately 2 kg in 35-42 days while consuming only 3.2 kg of feed. Genetic selection is still leading to improvements in performance and the time it takes to reach market weight is gradually becoming shorter. Around 50-60% of the improvement in growth rates over the last 50 years is due to improved breeds of chicken; this genetic gain, which has been achieved through conventional selective breeding, is due to:

  • investment in advanced breeding programs by the large well-resourced specialist breeding companies overseas;
  • the number of generations that can be produced in a relatively short period of time.

A further 20-25% of the improvement in growth is due to improved nutrition. For current meat chicken breeds, the precise profile of nutrients such as energy, protein, essential aminoacids, vitamins and minerals that the chicken needs at each stage of its growth has been studied precisely. For each feed ingredient, the levels of these nutrients digestible by the chicken has also been established. With this information, feeds can be formulated to match the chicken’s precise nutritional requirements throughout its lifecyle, thereby optimising growth.
Other gains made in meat chicken growth and performance are due to better husbandry techniques and health management.

Breeding

Hybrid production scheme.

Hybrid production scheme.


Meat production

Broiler production

Broilers gain their weight incredibly fast.
Typical performance figures for modern units can be summarised thus:

  • slaughtering age of birds ~ 43 days
  • slaughtering weight ~ 2.2 kg
  • % usable meat ~ 70 %
  • food conversion ratio 1.9 (amount of food required to produce weight gain)

In just a few weeks, the broilers are ready for slaughter. This is half the time it would take traditionally. This compares with free-range chickens which will usually be slaughtered at 8 weeks, and organic ones at around 12 weeks.

Meat production – Processing

When chickens arrive at the processor they go through the following sequence:

  • hanging by the legs on a shackle;
  • stunning using an electrically charged water bath;
  • killing by cutting the blood vessels in the neck;
  • bleeding so that most blood has left the carcass;
  • scalding to soften the attachment of the feathers;
  • plucking to remove the feathers;
  • head removal;
  • gutting or evisceration to remove the internal organs;
  • washing to remove blood and soiling from the carcass;
  • hock cutting to remove the feet;
  • chilling to prevent bacterial spoiling;
  • draining to allow excess water to drip off the carcass;
  • weighing;
  • cut selection to divide the carcass into desired portions.

Meat production – Processing

During the processing sequence, grading of carcasses is done at convenient times to remove poor quality meat which is used for cut-up (further processing) purposes or, if badly affected, might be used for pet food, or condemned and cooked to be made into meat meal for stock feed.
Further processing includes cutting up into portions, deboning carcasses and preparing special ready-to-cook products.

Meat production

Carcass and commercial cuts.

Carcass and commercial cuts.


Meat nutritional value

Poultry meat is not substantially different from red meat.
Dietary guidelines sometimes include advice to substitute, at least in part, chicken for red meat.
Chicken flesh has less saturated fatty acids and more PUFA than lean meat. However, it is necessary to remove the skin with the adhering subcutaneous fat, to reduce the fat content.
White meat has shorter muscle fibers that are less bound together with collagen.

Meat composition

Chemical composition of the different body parts.

Chemical composition of the different body parts.


  • Contenuti protetti da Creative Commons
  • Feed RSS
  • Condividi su FriendFeed
  • Condividi su Facebook
  • Segnala su Twitter
  • Condividi su LinkedIn
Progetto "Campus Virtuale" dell'Università degli Studi di Napoli Federico II, realizzato con il cofinanziamento dell'Unione europea. Asse V - Società dell'informazione - Obiettivo Operativo 5.1 e-Government ed e-Inclusion