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Chicken Litter Issues Associated with Sourcing and Use
by G A Runge, P J Blackall, K D Casey
January 2007
RIRDC Publication No 07/035 RIRDC Project No WS990-19
Who is the report targeted
at?
The report was designed
to provide information to help the RIRDC Chicken Meat Advisory Committee
evaluate the needs and priorities for further research into the availability
of and alternatives for meat chicken bedding materials, and the use, management
and disposal of litter. This project will therefore provide a framework
for future activities by the RIRDC in the area of chicken litter use and
management.
However, the report will also provide a valuable source of information for chicken growers and other industry participants on the management of litter and the potential impact of litter management practices on bird health, food safety and litter quality and acceptability to end-users. It will also be of value to researchers interested in identifying research needs and opportunities in this area, and to litter end-users and regulators concerned about potential risks and benefits associated with the use of litter as fertiliser and soil amendment, and for other purposes.
Background
The Australian poultry industry
and the community generally are concerned about the management of chicken
litter, from sourcing the initial bedding material through to utilisation
of the by-product. There is the potential to value add to chicken litter,
increase returns from it and reduce litter costs to chicken growers.
The community however, has some concerns about litter being spread on land, the associated odour emissions and the potential contamination of water tables and streams with nutrients and pathogenic organisms.
Consumers are demanding “clean” food. Farmers must guarantee, through participation in quality assurance programs, that their produce (milk, vegetables etc) is not contaminated with microbes likely to cause disease or contain undesirable antibiotic and chemical residues.
Government bodies expect that when chicken litter is applied to land as a fertiliser or soil conditioner that:
Around the world, the
use of composted organic materials is gaining economic credibility in mainstream
agriculture. It is apparent that a growth in demand for composted green
organic products is occurring in parts of Australia. There is an opportunity
for the chicken and litter value adding industry to participate in this
growth by developing suitable products incorporating chicken litter.
Future regulations on greenhouse gas emissions may affect the way chicken litter is managed to minimise greenhouse gases and ammonia release into the atmosphere.
Australian soils are infertile, low in organic matter and have a relatively poor soil surface structure. It is more desirable in the longer term to utilise chicken litter to improve soils than to burn it as an energy source as green energy, or to otherwise dispose of it as a 'waste' product of chicken production. The use of chicken litter as fertiliser would improve soil quality and the carbon level in soils and reduce the amount of carbon dioxide in the atmosphere. Returning secondary organic resources such as chicken litter to the land will increase the economic, environmental and social sustainability of Australian agriculture and food production.
The meat chicken industry spends $10.78 million annually on bedding material and receives about $0.71 million in return for the used litter. This leaves a cost of $10.07 million annually for bedding material.
There is the potential to value add to used litter and reduce the cost to industry for litter. About 1.17 million m3 of bedding material is used by the industry each year with approximately 1.60 million m3 of chicken litter available for utilisation.
Objectives
The objective of this project
was to develop a prioritised list of research or other actions required
to address a range of identified chicken litter issues associated with
the sourcing of bedding material, chicken shed litter management practices
and the utilisation of litter.
Methods
An email discussion group
was established by the project team to assist in the development of a list
of issues and to communicate information about the project and chicken
litter to participants. It also assisted in ascertaining what was known
about the topic. A literature search using library services and the internet
provided more information. A survey of the industry quantified the current
situation. These activities were followed by a workshop to prioritise the
issues and actions/research required to address them. The issues considered
at the workshop were:
Key findings and their
implications
Public health issues
Poultry litter can contain
a number of pathogens and other materials that are a potential risk to
public health (heavy metals, antimicrobial agents including the genes that
confer resistance to these agents and endocrine disruptors). The range
of pathogens present in poultry litter is less than that present in both
human effluent and the effluent produced by other intensive animal industries.
The pathogens and health risks that are of most concern to the litter contractors, value adders and end users are: Campylobacter jejuni Clostridium botulinum Salmonella spp.
Antibiotic resistance genes (in both normal flora and pathogens) Both composting and partial composting (defined as achieving a temperature of 55oC for at least three days) achieve a reduction in the pathogen load of chicken litter. Partial composting or deep stacking has the potential to pasteurise chicken litter ensuring that it is free from pathogens and providing a product at a cost likely to be acceptable for application to vegetables, fruit, crops and soils used for growing pastures for stock.
Quality assurance
Qualitative and Quantitative
Risk Assessment methods offer a valid and useful method for the establishment
of guidelines for the safe use of poultry litter.
There is potential for further market development of litter products if the industry can produce used litter of consistent quality. The litter contractors require used litter of consistent and known quality so that they can prepare and supply a product that consistently meets the requirements of their particular market and which meets relevant standards.
There is a need for chicken growers to be aware of the quality standards for used litter required by litter contractors and value adders to ensure that they can produce a product meeting the standards required by their customers.
The traditional litter contractors may require additional skills and knowledge to be able to effectively implement quality assurance programs appropriate to the changing needs of their end users.
Quality assurance of chicken litter production and processing systems will be crucial in ensuring long term market access and financial returns.
Environmental concerns
Poultry litter has useful
properties as a fertiliser and soil amendment and has been used for many
years in the production of a range of crops and products for human consumption.
However concerns exist regarding litter contaminants, including heavy metals
and pathogens.
Application rates in some situations, such as sandy soils and turf farming, have exceeded plant requirements with the potential for environmental damage from infiltration and run off of excess nutrients. Stricter guidelines in the future will restrict application rates to crop uptake and removals requiring supplementation with inorganic fertilisers to match crop nutrient demand.
The application of unprocessed poultry litter to vegetable and some fruit crops has declined sharply in recent years due to concerns over the microbial safety of food crops produced.
Processes including composting, pelleting and blending of chicken litter have been developed to produce value-added products for specialised, high value markets.
Energy recovery from the biomass in poultry litter as heat for electricity generation provides an alternative use for poultry litter although destroying valuable plant nutrients and soil organic matter in the process.
Single use and reuse of
litter
Single use of litter is
practiced by about 70 percent of the chicken industry. Those advocating
this practice claim that single batch clean out and disinfection result
in the most productive performance, lower downgrade level, more consistent
performance and lower cost per kg of chicken produced.
Reuse of litter as a bedding material has the potential to reduce litter costs and ease pressure on new bedding material supplies in the States where supplies are restricted.
The critical test with litter reuse is whether chicken performance, biosecurity and bird health can be maintained. From an economic viewpoint, the changed performance, increased vaccination costs, and the use of litter additives must balance the savings in litter costs.
Some processors are practicing partial or full reuse of litter where it is considered that the farm’s biosecurity is high and disease and poor hygiene risk status low.
To implement a reused litter program, good management is essential to minimise stress on chickens and to reduce the risk and impact of a disease on the flock. A healthy immune system is also essential to ensure good chick performance and the ability of the chick to withstand disease challenge. Litter reuse may result in the chickens being exposed, during the first few weeks of the chick's life, to relatively low levels of pathogens, stimulating an immune response which will protect the bird against infection in later life.
There is considerable evidence that reused litter may pose less of a risk in terms of food safety pathogens (as opposed to the chicken pathogens mentioned above) than single use litter, providing litter is well managed and maintained in a dry state.
As dry used litter is generally antibacterial in nature, for pathogenic bacteria at least, there is a strong argument that litter reuse is not associated with any increased use of antibiotics.
There are potential alternative bedding materials available to meet any shortfall in supply that may occur due to pressure from the green waste and biomass energy industry or if the use of single batch litter increases. These alternatives, such as sand, the fibre remaining after tea tree oil distillation, soya bean hulls, peanut hulls and straw, require evaluating to determine their suitability and viability for use in Australia.
The key to maintaining pathogen risk at a low level is litter dryness. It is a key issue for both food safety and flock health. The biggest issue in both the USA and in Australia with reuse of litter is managing the potential for increased litter moisture and higher ammonia levels.
Moisture management in the shed affects litter dryness. Management of equipment and ventilation is critical in maintaining dry litter. The drier the litter the more dust is created in the shed. The damper the litter the more ammonia and odour is generated. Dust and ammonia have the potential to pose health problems for both chickens and staff working in the sheds. Ammonia levels of 5 ppm or more are detrimental to day old chicks and levels of 25 ppm will lower performance of growing chickens.
Field experience and published evidence indicate that some litter additives can reduce ammonia levels in the chicken shed. These additives require moisture to activate the process of tying up the ammonia. Too much moisture and they are used up too quickly. Too little and they do not work quickly enough.
There is conflicting evidence about whether the use of these additives leads to improvements in chick performance. Research results suggest that improvements in chick performance tend to be recorded in situations where the levels of ammonia in the shed atmosphere are higher than those generally experienced in meat chicken houses in Australia in which the litter and ventilation are well managed.
The use of litter treatments is cost effective for winter batches placed on reused litter in the USA. Both local and overseas experience suggests that litter treatments are not cost effective for single litter use where litter moisture management and ventilation are good.
The use of some litter additives should be seen as an aid to litter management, not the answer to poor management of ventilation and litter moisture. Good ventilation and management of litter moisture is part of ensuring the litter treatment works effectively.
Recommendations
The following are recommendations
for future research or other action:
 
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