Poultry litter
In agriculture, poultry litter or broiler litter is a mixture of poultry excreta, spilled feed, feathers, and material used as bedding in poultry operations. This term is also used to refer to unused bedding materials. Poultry litter is used in confinement buildings used for raising broilers, turkeys and other birds. Common bedding materials include wood shavings, sawdust, peanut hulls, shredded sugar cane, straw, and other dry, absorbent, low-cost organic materials. Sand is also occasionally used as bedding. The bedding materials help absorb moisture, limiting the production of ammonia and harmful pathogens. The materials used for bedding can also have a significant impact on carcass quality and bird performance.
There are specific practices that must be followed to properly maintain the litter and maximize the health and productivity of the flocks raised on it. Many factors must be considered in successful litter management including time of the year, depth of the litter, floor space per bird, feeding practices, disease, the kind of floor, ventilation, watering devices, litter amendments, and even the potential fertilizer value of the litter after it is removed from the house. Most poultry are grown on dirt floors with some type of bedding material. Concrete floors and some specialized raised flooring are used at some facilities. In many areas of the United States, shavings from pine or other soft woods have historically been the bedding of choice for poultry production. Regionally, other materials have been the bedding material of choice due to regional cost and availability, such as rice hulls in the lower Mississippi River poultry production areas of Arkansas and Mississippi.
Bedding materials
Growers consider a number of factors when determining which material to use as bedding in their facilities, with cost and availability being a major consideration. Bedding materials generally needs to be very absorbent, and must have a reasonable drying time. Many paper products, for instance, absorb moisture well but do not dry out appropriately. The material should also have a useful purpose once it has been used as a bedding material. Without a useful purpose for the used litter, poultry growers would need to dispose of unmanageable quantities of old litter. Large accumulations of litter stored unused for long periods of time are not ecologically acceptable even on a small scale, and would be non-sustainable from an industrial perspective.Poultry bedding materials also have to be reasonably available. Some materials may meet industry goals once under the birds but if it is difficult to obtain, it will not find favor as a poultry litter. Finally, if a material is not cost competitive with current materials utilized, it will also not be used as a litter material. However, if the new material has increased value once removed from the poultry house compared to current litters or if the current litter material itself becomes difficult to obtain or the quality is decreases, poultry growers may decide to use the new litter material.
Bedding material must not be toxic to poultry or to poultry growers. It should not be excessively favorable for the growth of the litter beetle, a major pest. The effect on other livestock, pets, wildlife, and even plants must also be considered. Poultry can consume as much as 4% of their diet as litter, therefore any bedding material must not contain contaminants, such as pesticides or metals. Consumption by the birds due to litter eating or other bird behavior could affect production and potentially cause the meat or rendered products to become unusable. Pine shavings has been the bedding of choice because of performance, availability, and cost.
Management practices
Moisture
The heating and ventilation systems in a poultry house must be continuously monitored to keep the moisture content of the litter controlled so that the litter remains friable. If the litter becomes too wet and the litter is allowed to become "sealed", then the birds will be living on a damp, slippery and sticky surface. This sealed litter is what is referred to as being "caked". In this condition, the litter is simply saturated with water and is unable to dry out. A severe problem with litter moisture will result if large areas of the house floor surface are caked. The more common issue, however, is having localized areas of caking near leaky watering cups, nipples, troughs or roofs. Watery droppings caused by nutrition and/or infectious agents can also be a cause of excessive moisture in poultry litter.If litter is not kept at an acceptable moisture level, very high bacterial loads and unsanitary growing conditions may result producing odors, insect problems, soiled feathers, footpad lesions and breast bruises or blisters. This can affect the health and mortality rate of the flock, and could result in quality issues when birds reared under such poor conditions reach the processing plant. In a well-managed broiler house, litter moisture normally averages between 25 and 35 percent. Litter that is managed correctly with the moisture content kept within the acceptable range can be reused if no disease or other production problems occur. On the other hand, caked litter must be removed between flocks and replaced with new litter.
Litter re-utilization
Some broiler producers are simply removing cake and excess litter after house washing and then placing broilers on old litter for an extended number of flocks. Their expectation is that total clean out is not needed unless there some disease or other bio-security issues. However, producers doing this should be aware that total disinfection under these conditions is probably not possible.Re-utilization of at least some fraction of used litter as a supplement for fresh wood shavings bedding in broiler houses has been found to not significantly increase pathogens and indicator microorganisms in litter compared to using fresh wood shavings. No consistent significant differences have been found regarding flock performance when comparing houses using fresh litter with houses re-utilizing litter.
A major issue with re-utilization of previously used litter is the generation of ammonia. Ammonia is produced by microbial breakdown of fecal material in the litter. It is well documented in the literature that higher moisture levels result in higher ammonia production. The caked portion of the litter is very high in moisture and nitrogen and should be removed from the house to reduce ammonia generation and provide optimal air quality for chicks during the brooding period. Add litter treatments to reduced ammonia generation. Controlling ammonia with a litter treatment can save money on energy costs by reducing the amount of air exchange required to maintain adequate air quality.
Litter amendments
High ammonia levels in poultry houses can result in poor bird performance and health and a loss of profits to the grower and integrator. When broilers and turkeys are raised on litter, amendments can be used to reduce ammonia levels in the houses and improve productivity. Uric acid and organic nitrogen in the bird excreta and spilled feed are converted to ammonium by the microbes in the litter. Ammonium, a plant-available N form, can bind to litter and also dissolve in water. Depending on the moisture content, temperature, and acidity of the litter, a portion of the ammonium will be converted into ammonia. Ammonia production is favored by high temperature and high pH. Ammonia is a pungent gas that irritates the eyes and respiratory system and can reduce resistance to infection in poultry. At high-enough concentrations, ammonia will reduce feed efficiency and growth while increasing mortality and carcass condemnations. The result is economic loss to the grower and integrator. Because chicks are more susceptible to the negative effects of ammonia, placing broods in houses with high levels of builtup litter is particularly harmful. Also, the high temperatures required during brooding increase ammonia levels, and moist litter and insufficient winter ventilation contribute to high ammonia levels as well. In these situations, some growers rely mainly on ventilation to reduce ammonia in the houses. However, ammonia loss from the litter reduces its fertilizer value, and venting ammonia into the environment can cause health and environmental problems.There are several types of litter amendments available to manage ammonia the most common being acidifiers, and various microbial and enzymatic treatments.