Organic rearing of broilers is not a large production in Sweden. In order to create a sustainable yet efficient production of organically produced poultry meat, at a price that the consumers are willing to pay, much more knowledge is needed. It is therefore important to do more research on organic broilers under Swedish conditions. This report is aimed to be a base for further studies.
In the study 2000 broilers of the hybrid Ross 308 divided in to two equal groups. The broiler hybrids that are used in Sweden are selected for a high growth rate and are normally slaughtered at the age of 5 to 6 weeks, with a slaughter weight of 1.7-2 kg. They are presumed to be less suited for rearing to a higher age. The broilers in this study were reared according to the rules of organic production to an age of ten weeks and reached a slaughter weight of approximately 4.5 kg. Rearing these hybrids to such a high slaughter weight can have a negative impact on the health and wellbeing of the broilers, mainly considering the leg health. Numerous birds in this study had to be culled due to different leg problems. A slower growing hybrid would be desirable in organic broiler production, but is not available in Sweden at the moment.
The broilers were kept indoors in a warm stable on the floor with wood shavings until the age of 25 days. Then they were moved to an outdoor stable with a daily access to pasture. The size of the pasture was 4 m2 per chicken. Only a small number of the broilers made use of the pasture despite the set up wind shields. The broilers preferred to be outside for half an hour in the morning, and spent the rest of the day inside the outdoor stable, close to feed and water.
In the study two different organically approved broiler feeds (according to the rules of KRAV) were compared. The first group got a more traditional feed consisting of organic soy expeller and fish meal. The second group got a feed based on protein feedstuffs that can be produced locally in Sweden such as potato protein, malt sprouts and peas.
For poultry the most important essential amino acids are metionin and cysteine. These amino acids are very important components in the development of feathers. Most feedstuffs that are used today in broiler feed have a low content of sulphuric amino acids compared to the needs of the birds. In conventional production this is not a problem since one can add synthetic amino acids however this is not permitted according to KRAV-regulations. Hence, to get a sufficient amount of essential amino acids in organic production it is often necessary to over feed proteins. It is very important with a well-balanced feed with a sufficient level of amino acids but with relatively low energy content. This is to keep the chickens healthy without getting too heavy. If they do get too heavy they often tend to get leg and feet problems.
The result of the study showed no large differences in growth rate, feed conversion (approximately 2.8 kg feed/kg chicken for both groups) or mortality (at about 15 %) between the groups. In the group that got locally produced feed a total of 17 broilers were killed by predators. At the age of three weeks there was a cannibalism outbreak in the ...
