According to David McCreery, project and farm manager for the University of Arkansas Applied Broiler Research Farm, decaking is a process necessary to remove the product caused when water, feces and bedding combine to form a ‘cake’ on top of the bedding, typically rice hulls or wood shavings, in a poultry house.
“In the process they use a special machine to remove chunks of manure and clumped litter that accumulated,” said John Lory, extension associate professor with the University of Missouri’s Division of Plant Sciences. “The process leaves behind most of the litter to be used again by the next flock.”
According to Lory, decaking is done every time another set of birds is cycled through the building.
Frequency of decaking is also determined by the size of the bird, McCreery added. “The larger the bird desired, the longer the growout period, the greater time between decaking.”
“The cake contains concentrated levels of ammonia,” McCreery said. “It is removed to help lower the ammonia levels in the house. This improves the air quality, which can decrease heating and ventilation costs. Additionally, lower ammonia levels improve the birds’ production efficiencies. Cake typically contains about 40 percent moisture. Removing cake also helps control moisture levels in the house.”
McCreery said that the equipment used to do the process is called a ‘Housekeeper’ and is pulled with a tractor. “The housekeeper is adjusted to skim the cake off the top of the bedding and pulled throughout the house.”
According to Lory, cake litter is either then applied to land or stacked in stack houses until there is an opportunity to use it as a fertilizer for crops.
“It can also be burned to produce steam for a boiler or in the production of electricity,” McCreery said.
“After decaking is complete, the house is ready to be set up for the next flock,” McCreery said. “The grower can till the litter to further reduce moisture levels within the house. In addition to or instead of tilling, the litter can be windrowed. This is a process similar to composting, which results in a lower bacteria level in the litter.”
Litter should be tested before each cleanout. “Ideally all manure is applied based upon the results of a manure test to meet the fertilizer needs of a crop,” Lory said. “Cake litter may have lower nutrient concentrations then typical litter and definitely will initially have higher moisture content.”
According to McCreery, each producer has a permit issued from the state that outlines the producer’s obligations under the state and federal laws regarding the handling of litter.
Rules for spreading poultry litter are similar to that of other manures on permitted animal feeding operations. These rules include the requirement to test all manure sources at least annually, to observe setbacks from water features when applying manure and to keep records on manure management.”
Lory concluded that most producers who have barns are very familiar with this process and the regulations. “The biggest needs are to ensure growers know to manage the cake manure appropriately as it arrives at all times of the year, stack houses address these issues.”
