Organic poultry farming needs its own breeds of chickens

A review of twenty years of scientific research at the University of Perugia, Italy, showed poor adaptability of commercial chicken hybrids to the organic production system.

The demand for poultry meat, which is cheaper than beef, is driving the production of this product around the world.

In 2025, poultry production is expected to increase to 16%. Thus, the production of poultry meat will increase from 115,192 thousand tons in terms of in 2016 to 131,255 thousand tons by 2025.

Argentina, Brazil, Mexico, Russia , Ukraine and the United States will be the leading producers. In Asia, the leaders will be China , India, Indonesia, Iran and Thailand.

The majority of poultry meat production is carried out through intensive production systems, and extensive rearing systems (ERS) for poultry (organic, free-range and low resource consumption) make up only a small part - specifically in the EU about 5%.

However, the growing interest in such growing systems to maintain a good product image and environmental sustainability is increasing with an annual growth trend of about 10%.

The aim of the researchers of the Department of Agriculture, Food and Environmental Sciences of the University of Perugia unit is to determine the best poultry genotypes for ERS, which are important not only for the food industry, but also for the health benefits of the human consumer.

ERS systems are less standardized than intensive systems and are not the same in all countries. There are even major differences between countries in the European Union due to climate, working conditions and feed costs, the availability of alternative genotypes and land resources, and the willingness of consumers to pay for premium products.

As far as organic systems are concerned, in general chickens should have access to an abundance of fresh air, daylight and open space, and live as naturally as possible.

When it comes to organic poultry feed, the requirements are very strict in the EU. A minimum of 20% of feed must be locally or regionally produced. Grains must not contain GMOs and there are a number of restrictions on pesticides and fertilizers used in growing feed.

Twenty years ago, scientists from the University of Perugia concluded: “It is useless to give a lot of space to chickens that cannot use it ... but at the same time it is useless to use chickens that can feed without pasture and ranges.”

In fact, in some countries it is common practice to grow commercial meat-type broilers in the ERS system, however, these are not the poultry genotypes that are needed in organic production.

What is needed is a type of chicken that is better suited to the natural environment. Accordingly, other features such as activity, exploratory attitude, immune response, thermotolerance, and social interaction must be taken into account.

In the scientists' experience, Ross 308 male hens were assigned to two different rearing systems: conventional (indoors with 0.12 m2 per bird) and organic (placement in a chicken coop 0.12 m2 per bird with access to a grassy pen, 4 m2 per bird ).

Although the results showed good meat quality in organic poultry, high levels of lipid oxidation and the appearance of behavioral features (higher lying frequency, lower kinetic activity) and carcass defects raised doubts about the real possibility of using commercial hybrids in organic cultivation.

In subsequent experiments, the scientists compared the performance and behavior of three varieties of chickens within the organic rearing system described above.

Chickens had a very slow growth of Robusta Maculata, a slow one - the Kabir breed and a fast one - Ross 308.

Chickens of the Kabir and Robusta Maculata breeds showed greater intensity of walking activity, better feeding and health. While Ross 308 hens showed good growth rates, carcass weight, but mortality and culling rates were higher, indicating that fast growing birds were not able to adapt well to organic production.

Mortality was 10, 5 and 4% respectively for Ross 308, Kabir and Robusta. Sensors weighing 50 g, mounted and mounted on the back of the bird, recorded the time that the animals spent voluntarily grazing: 35, 60 and 65% of the total time for Ross 308, Kabir and Robusta, respectively.

Ross 308 and Kabir hens were ready for slaughter in 81 days, while the Robusta breed took 120 days to reach marketable weight (body weight > 2 kg).

The meat of all three genotypes showed good quality characteristics, but the meat of Ross 308 was more fat and pale.

The first thing that comes to mind is to keep looking for the perfect chicken for the ERS system.

Many other interdisciplinary studies are already underway to explore aspects related to the identification of genes responsible for adaptability characteristics and their expression, based on an in-depth study of the relationship between kinetic activity, grazing behavior, antioxidant capacity (blood and meat), nutritional value of the final product.

Second. Clearly, local poultry breeds around the world are under threat of extinction due to being replaced by productive competitors. However, some of these local breeds may have the traits and genes necessary to adapt to ERS (i.e. heat stress tolerance, high immune response, kinetic activity and some beef characteristics).

For this reason, it is necessary to maintain and increase the presence of local breeds of poultry. For example, recently in Italy, a genealogical book of poultry was developed, which included 22 breeds of chickens, as well as breeds of turkeys, ducks, geese and pigeons. 

Five Italian native chicken breeds (Ancona, Livorno, Modenese, Romagnola and Valdarnese Bianca) were examined based on mitochondrial DNA information. Moreover, the degree of genetic diversity, population structure and genetic relationships between these populations was assessed using 27 microsatellite markers.

Also, the genomic variation of local Italian chicken breeds was studied using single nucleotide polymorphisms (SNPs) to understand their genetic diversity and population structure. This was necessary to understand that these breeds have retained authentic genetic samples and are suitable for further selection.

Based on an article by research authors from the Department of Agriculture, Food and Environmental Sciences of the University of Perugia (Alessandro Dal Bosco, Simona Mattioli, Alice Cartoni Mancinelli, Elisa Cotozzolo, Cesare Castellini) published in Animals 2021 on the MDPI portal.