ANR-804 Mini-Composters In Poultry Production
ANR-804, Reprinted Jan. 1996. James Donald,
Extension Agricultural Engineer; John P. Blake, Extension Poultry Scientist; Kevan
Tucker, Extension Associate--Environmental Management; and David
Harkins, Extension Associate--Environmental Management
Mini-Composters In Poultry Production |
In 1992, Alabama ranked second in the nation in broiler production and
produced approximately 900 million broilers, valued at nearly $1 billion.
The poultry industry generates nearly half of every agricultural income
dollar in Alabama, and current research estimates that production will expand
20 percent within the next 3 years.
While Alabama's poultry industry produces 18 million broilers every week,
it generates 800 tons of carcasses weekly, as well. Every broiler production
facility must face the reality of dead birds. Disposal of dead birds could
be a serious environmental problem that may limit future expansion of the
industry in Alabama.
Disposal Methods And Environmental Concerns
Producers most commonly use burial pits for the disposal of poultry carcasses.
However, when residue remains in pits after years of use or in soils with
high groundwater tables, reduced surface and groundwater quality is a serious
potential problem. In some states, such as Arkansas, legislation has been
enacted to prohibit the use of burial pits.
Incineration is biologically the safest method of disposal. However,
it is slow, expensive, and generates nuisance complaints even when highly
efficient incinerators are used. Incinerators also generate particulate
air pollution.
Concern over possible environmental damage and newly imposed local, state,
and federal water and air quality regulations make alternative disposal
methods of interest to the producer. Deadbird composting is one such alternative
that the state Veterinarian's office, state and local health departments,
the Alabama Department of Environmental Management, and the Soil Conservation
Service (SCS) have approved.
Poultry Carcass Composting
Testing and adoption of composting as a method for the disposal of poultry
carcasses began in Alabama in the late 1980s. Since 1989, Alabama poultry
farmers have constructed more than 500 freestanding carcass composters.
Poultry producers have readily accepted the composting of poultry carcasses,
but operating the composter requires a tractor with loader for loading,
turning, and removing the compost.
Because large broiler farms--those with more than two poultry houses--use
tractors and loaders in their farming operations, they have adopted poultry
carcass composting. On the other hand, small broiler farms--those with only
one or two broiler houses--do not have tractors or loaders and have not
adopted composting. About 50 percent of the 6,000 Alabama broiler farms
fall into this last category.
Small-Scale Composting
In other states small-scale producers have constructed mini-composters
for use in the broiler house. Researchers at the University of Delaware
tested simple, single-stage composters (Scarborough, et al., 1992). These
small composter bins were placed within the confines of the broiler house,
and carcasses, straw, caked litter, and water were added daily. In Alabama,
however, most producers usually place mini-composters outside of the broiler
house.
Mini-composting works well for grow outs of approximately 7 weeks. If
producers are growing large birds, added capacity may be required.
Building The Mini-Composter
The simplest design for a mini-composter consists of a wooden box to
hold dead poultry and other composting materials. The portable compost box
developed at Auburn University is 4 feet by 4 feet and 4 feet high with
removable side panels. The box is constructed from pressure-treated lumber
with 1/2-inch air spaces between side boards (figure 1).
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Figure 1. Small-scale
composting boxes with fronts removed. |
The box can handle normal bird mortality (two to four carcasses per thousand
per day). An average 20,000-bird house requires four to five compost boxes
to handle normal bird mortality. Small-scale composting cannot accommodate
the carcasses from larger die-offs. Larger die-offs require other disposal
methods.
While mini-composters were originally designed to be used inside the
poultry house, in Alabama compost boxes are placed under a small structure
separated from the poultry house (figure 2). Cost estimates for the structure
and compost boxes do not exceed $1,500 for a two-house operation.
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Figure 2. Mini-composting
structure with compost boxes. |
A number of programs are available to help poultry producers reduce the
cost of building composting structures. Contact the local Conservation District
office, the USDA Agricultural Stabilization and Conservation Service (ASCS),
or the SCS about cost-share funds for the construction of composters.
Operating The Composter
For successful operation, the composter must be properly loaded. First,
place a 6- to 8-inch layer of manure cake (litter) in the bottom of the
box. Then add an appropriate amount of straw, according to the composting
formula, to aid in aeration and to provide a source of carbon (see table).
After these two layers, add ingredients according to the formula, beginning
with a layer of carcasses, then a layer of litter. Be sure to keep the carcasses
at least 6 to 8 inches away from the sidewalls of the bin. This will eliminate
fly and odor problems. The litter is readily available as caked or uncaked
material from the floor of the broiler house. If the litter is dry you may
need to add water to it.
Formula For Dead Poultry Composting.
Material |
Parts By Weight |
Poultry Manure (Litter) |
2 to 3 |
Straw |
1/10 |
Poultry Carcass |
1 |
Water (Add sparingly.) |
0 to 1/2 |
For the next and all subsequent layers, begin with straw; then add carcasses
and manure, in that order. As the grow-out proceeds, add successive layers
of material to the box. After you add the last layer, place the final cover
or cap of a double layer of manure over the top. Do not add water to this
final cap (figure 3).
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Figure 3. Layering of
ingredients in composter box. |
NOTE: The purpose of the straw is to add air voids and allow aerobic
decomposition of the mixture. Many producers who use caked material have
successfully composted without straw, but the individual producer must decide
whether or not to use straw. You can achieve good temperatures without straw;
however, proper management of the box becomes much more important.
When adding additional water for composting, keep in mind the moisture
content of the litter. The moisture content of poultry litter or cake may
vary from 20 to 40 percent depending on the source. In small-scale composting,
adding water to achieve a 50- to 60-percent moisture content is much more
important than in large-composter management.
Monitor the temperature in the compost bin with a 20-inch, probe-type
thermometer. After a few days, temperatures increase rapidly because of
bacterial action, rising to 130°F or greater. After 7 to 10 days, the
pile reaches its high reading of 130° to 150° F, which helps stabilize
the compost. Once temperatures begin to decrease, you can easily move the
composted material to storage.
Land Application Of Compost
Compost is stored in a weather-protected structure until proper time
for land application to meet field or forage crop needs. Nutrient content
of compost will vary depending upon the amount and nutrient content of the
manure, the age of the compost, and the method of storage.
The rule of thumb for nutrient content of compost is as follows:
Moisture |
28.0 percent |
Nitrogen |
1.9 percent |
P2O5 |
2.3 percent |
K2O |
1.6 percent |
To be land-applied like fertilizer, compost must meet crop needs through
a balanced nutrient content. Compost should be applied as close to planting
as possible and should be incorporated with normal soil tillage operations.
Conclusion
Alternative methods for the disposal of poultry carcasses are limited,
and mini-composting presents itself as a desirable environmental and economic
option. Applied research conducted at Auburn University in the early 1990s
demonstrated that small-scale composting puts an effective and simple composting
system within the reach of virtually every poultry producer.
The mini-composter fills the need for a small, simple composter that
can process complete growout mortality on small to medium-sized farms. The
operation is simple, yet highly effective, and construction costs are reasonable.
Mini-composters may also be useful in periods of light mortalities on larger
operations.
References
Conner, D. E., J. E Blake, J. O. Donald, and J. S. Kotrola. 1992. Composting
Poultry Carcasses: Microbiological Safety. Proceedings: 1992 National
Poultry Waste Management Symposium, pp.418423.
Donald, J. O., and J. E Blake. 1990. Dead Poultry Composter Construction.
Circular ANR-604. Alabama Cooperative Extension Service, Auburn University,
AL.
National Poultry Waste Management Symposium Committee, Auburn, AL.
Scarborough, J. N., D. H. Palmer, and T. H. Williams. 1992. Composting
Structures For Dead Poultry Disposal. Circular Q-4. University of Delaware
Cooperative Extension, Newark, DE.
For more information, contact your county Extension
office. Look in your telephone directory under your county's name to find
the number.
For more information, contact your county Extension office. Visit http://www.aces.edu/counties or look in your telephone directory under your county's name to find contact information.
Issued in furtherance of Cooperative Extension work in agriculture and
home economics, Acts of May 8 and June 30, 1914, and other related
acts, in cooperation with the U.S. Department of Agriculture. The Alabama
Cooperative Extension System (Alabama A&M University and Auburn
University) offers educational programs, materials, and equal
opportunity employment to all people without regard to race, color,
national origin, religion, sex, age, veteran status, or disability.
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