Management Guidelines for Windrowing Litter Between Flocks

Bud Malone

Malone Poultry Consulting Princess Anne, MD

(malonepoultryconsulting@gmail.com)

The following guidelines represent the current (2009) information for in-house windrowing of litter between flocks. This information is based upon research and observations during the past few years on Delmarva and other regions of the country. The procedures may be modified in the future as more experience is gained with this litter management technique. Furthermore, the guidelines are based mostly on Delmarva broiler production practices, housing, litter management, climate and formation of piles using windrowing equipment. Modifications to these procedures may be needed for other regions of the US and with other species of poultry.

1. The ideal time to start in-house windrowing of litter is the first flock following a total clean-out. If starting with built-up litter, it might be best to implement windrowing during warm or moderate weather to minimize the challenge with controlling ammonia during the initial windrowed flock.

2. Windrowing should be implemented within 2 days following bird movement. If the litter is dry (~20%) it may be beneficial to close the houses prior to windrowing to minimize moisture loss.

3. One must manage litter depth in the range of 3 to 6 inches. If depth excesses 8 inches, a portion of the litter should be removed at least on an annual bases. This may be done in spring or fall and when there is adequate storage for the litter, land available for spreading according to nutrient management plans or other suitable alternative uses for the litter.

4. If caking excesses 3 feet wide and/or 3 inches thick under the nipple lines, it may be necessary to re-crust the house after the windrowing process. During cold weather it may be beneficial to remove this excessive cake before building the windrows.

5. When starting with built-up litter that has an excessive hard pan, windrow the loose litter and either remove the hard pan from the house or break it up sufficiently for incorporation into the windrow. In cold weather, it would be best to remove this hard pan from the house. In warmer weather and with dry litter, the hard pan may be incorporated into the windrow as an added source of moisture. Since it has been suggested that one of the benefits of windrowing is exposing the dirt floor to the atmosphere on a regular bases, as much as practical, removing all litter and hard pan from the floor is generally recommended.

6. The optimum windrow size is ~18 to 24 inches high and conical shape. This size windrow heats rapidly, is ease to turn and allows maximum moisture and ammonia release. The number of windrows per house will depend on litter depth and house width. All litter, including that under the windrow base should be turned and go thru the heating process.

7. From a pathogen reduction standpoint the goal is to reach at least 130 F and maintain these temperatures for a minimum of 3 to 5 days. Approximately 3 days after constructing the windrows the piles should be turned. Turning exposes the cooler portion of the pile to the higher temperatures. It is important to monitor and record temperatures daily. An inexpensive digital thermometer with a 1 foot long probe inserted into the top of the pile is one option for monitoring windrow temperatures. Since temperatures vary at different depths and piles vary in height, for consistency purposes, it may be helpful to place the temperature probe at 50% of the pile depth.

8. For farms with a significant disease challenge, it would be best to remove all litter from the sidewalls and corners and incorporate this litter into the windrow. Any undistributed litter under the windrow base should also be incorporated during the turning process. A wash down prior to windrowing incorporates the pathogen-laden dust into the pile and adds moisture, aiding in increased compost temperatures and pathogen kill. Additionally, for farms with a significant disease challenge, it may take 2 consecutive windrowing events (flocks) to break some diseases (ie. dermatitis) and the disease may re-appear if the litter is not windrowed for 2 consecutive flocks.

9. A minimum of a 10 day layout is often needed to implement the windrowing procedure. Windrowing should be avoided if there is inadequate layout time as sometimes occurs during summer flocks or in extremely cold weather with wet litter that does not allow adequate conditions for moisture and ammonia removal.

10. It is best to turn windrows at least once, and several times if possible. Turning helps release moisture and ammonia, may increase pile temperatures, reduce cake and increase the percentage of pathogen kill in the litter mass. If time permits, turning windrows on a 2 to 3 day cycle may be a consideration.

11. If caking or moisture is excessive, re-crusting the house after leveling the litter may be required particularly in cool weather.

12. If piles are formed with a skid-steer as sometimes required for pole houses, turning may not be an option. These larger piles tend to take longer to reach desired temperatures in the core of the pile. Although the amount of cake if often reduced by as much as 50% in the windrowing process, the house will need to be re-crusted after leveling the litter.

13. Within an hour darkling beetles will start migrating to the surface of a freshly windrowed pile. An ideal time to get maximum beetle kill may be to apply a quick-kill insecticide to the windrows within the first 12 hours after pile formation. Also, band application along the sidewalls should be considered if this litter is not incorporated into the windrow. If scheduling insecticide application immediately after pile formation is not an option, the regular pre-placement treatment can be used. There may be an opportunity to decrease the frequency of insecticide application since windrowing aids in reducing darkling beetle populations.

14. Closing houses following windrowing to retain house temperatures will have little impact on windrow temperatures! More important, in a closed house there will be very high (and dangerous) levels of ammonia, carbon dioxide and moisture. For solid sidewalls houses during warm and moderate weather, several tunnel fans should be run continuous with air being pulled thru the inlets. In colder climates it may be necessary to reduce air flow by running minimum ventilation fans set on timer or thermostat. Ventilation to remove ammonia and moisture should be provided from the day of windrowing until chick placement. When the windrows are being turned, maximum ventilation should be provided to help remove the moisture and ammonia as it is being released from the steaming piles.

15. All operators should wear a respirator with ammonia filters when constructing, turning and spreading windrows.

16. The windrows can be spread out and leveled with a blade, skid-steer and/or windrowing equipment. Box blades and windrowing equipment with an adjustable skid to get consistent depth works well. It is critical adequate time be devoted to get the litter level. Leveling the piles at least 4 days prior to chick placement is generally recommended. When the layout schedule permits, leaving the windrows piled for a minimum of 7 days, and 10 day if possible, may promote additional ammonia and moisture volatilization losses.

17. To minimize the potential for high ammonia levels in the subsequent flock following windrowing, it is essential to follow the steps previously mentioned. Higher levels of litter amendment (~25% more) may be required particularly in cool weather to suppress ammonia. Litter amendments should not be applied within 2 days after leveling the piles. Higher ventilation rates may also be needed during brooding to control ammonia when first initiating a windrowing program. Ammonia control tends to be more manageable after the first or second flocks once starting the windrowing program on built-up litter. Failure to control ammonia during the brooding period can result in poor performance and partially defeat the benefits of the windrowing program!

In-House Litter Composting Between Flocks

Blake and R.A. Norton, Poultry Science Department, Auburn University, Auburn, AL Composting litter between flocks has become an accepted method for reducing microbial loads in broiler houses during times of the year when removing and replacing litter is inconvenient or infeasible. Recently, replacement litter (bedding) materials have been in short supply, increasing replacement cost in addition to making bedding unavailable at times. Poultry companies and growers alike are embracing the concept of in-house windrow composting as a way to improve bird performance and reduce the likelihood of disease spread when total cleanout is not a good option. As this management tool gains support, techniques to get the most out of in-house composting are being fine-tuned by the growers and equipment manufacturers that support them. The benefits of composting as a method of dead bird disposal have been known and practiced for several decades (Murphy, 1988, Brodie, et al., 2000). Monitoring of compost of this type tells us that bacterial and viral pathogens are eliminated or greatly reduced. Others have composted litter to reduce pathogens and produce consumerfriendly fertilizer products (Anderson, 1990). During the last few years, broiler producers have refined methods of in-house litter composting with the intent of using this technique to reduce bacterial and viral loads between growouts and allow the reuse of litter for an extended period of time. In most cases, growers have used a box blade or compost turner to create two long windrows in each house to most effectively allow the litter to go through a heat. Creating windrows will require several hours of work per house. Respreading litter after composting will take a similar amount of time. Cake may be removed or may be left in to provide enough moisture for the bacteria to proliferate if litter moisture is low. Practical trials run by Theresia Lavergne at LSU (Lavergne et al., 2004) suggest that 30% moisture is necessary for best results, while most broiler houses show less moisture than this (20-25% moisture). Temperatures of 130 F or greater are created to reduce bacterial numbers and kill or reduce most viral pathogens. If in-house composting is used to reduce microbe numbers after a flock has shown disease problems, the house temperature may be heated to 100 F as the composting is completed to further reduce microbe numbers. Obviously, this would be easier to accomplish in the summer than during other seasons. Auburn research shows that maximum temperatures (130 – 140 F) are reached within 36 hours of windrowing and temperatures typically begin decreasing after about 48 hours. This is long enough to kill many pathogenic bacteria and viruses and reduce the overall litter microbial load (Macklin et al., 2004, Macklin et al., 2006, Macklin, et al., 2008). Based on this, a three to five day in-house composting program between flocks would be a useful way to reduce viral and bacterial organisms and improve bird performance. Downtime between flocks needs to be 10-14 days to allow growers to complete the composting and still have time to prepare for chick delivery. A period of 5-7 days following respreading of the litter after in-house composting will allow the litter to cool down and release ammonia before preparing for the arrival of the next batch of chicks. Although this technique has been shown to be useful in times of disease challenge to reduce the risk of disease in the next batch of birds and to reduce disease spread as litter is removed from the house, windrow composting also makes sense from an economic standpoint. Reduced levels of the more fragile microorganisms such as LT and campylobacter would help to insure optimum bird performance and reduce human food safety concerns (Macklin et al., 2008). Reduced loads of other harmful bacteria and viruses allow birds to use feed for growth and performance rather than for fighting off mild (and often unseen) disease challenges. As importantly, litter ammonia levels should be appreciably reduced prior to placing the next batch of birds if sufficient time is given for ammonia to dissipate prior to placement of chicks. Each of these results allows for the continued use of litter such that cleanout and bedding replacement are not necessary unless convenient for the grower. For many poultry growers, frequent litter cleanout is a poor option because of seasonal limitations on litter spreading and limited availability of new pine shavings. For this reason, in-house composting of litter allows growers to boost performance and health. Although improvements in performance from litter composting between flocks may not mimic total cleanout and sanitation, health and performance improvements should be substantial and yield measurable dividends. Adopting this technique may allow growers to reduce microbes periodically if total cleanout is not convenient. Many poultry producers are moving toward extended use of litter to reduce the cost of replacement bedding materials over time. In-house windrow composting does not reduce the amount of litter that accumulates and, ultimately needs to be removed, but it does allow the farmer to remove that litter when farming practices or economic incentives dictate. This, in turn, allows for more prudent use of litter as a fertilizer, either locally or regionally. Litter mineral levels generally build up over time (consecutive growouts), with the exception of nitrogen (Lavergne et al., 2004). Due to this, the ratio of nitrogen to phosphorus and potash decreases with time, unbalancing the nutrient levels in an unfavorable direction. Windrow composting allows for the removal of ammonia prior to brooding for chick health. Unfortunately, this technique can reduce litter nitrogen levels even further (Lavergne et al, 2004). On the other hand, litter reuse may lead to humus production as the litter decays, tying up some portion of the minerals in the litter. This would reduce the amount of mineral runoff after land application and provide mineral nutrients over time as the humus is incorporated into the soil (Lavergne et al., 2004) In conclusion, in-house windrow composting can be used to reduce disease load in litter, extending litter life well beyond what poultry growers have experienced in the past. This technique can allow growers to reuse litter in such a way that cleanout can come when a favorable market exists for the litter and when replacement bedding materials are available. Unfortunately, both extended reuse of litter and windrow composting tend to reduce the ratio of nitrogen to other agronomically-important minerals.

References: Anderson, L., 1990. Commercial Composting of Poultry Manure. Proceedings of the 1990 Nat. Poult. Waste Manage. Symp., Raleigh, NC, Oct. 3-4, Pages 130-140. Brodie, H.L., L.E. Carr and P. Condon, 2000. Poultry litter composting comparisons. Biocycle 41:36-40. Lavergne, T.K., M.F. Stephens, D. Schellinger and W.A. Carney, Jr., 2004. Making poultry litter safe for reuse: In-house pasteurization can save money for producers. La. Agric. 47:4. Macklin, K.S., J.B. Hess, S.F. Bilgili, J.P. Blake and R.A. Norton, 2004. Bacterial counts associated with composting litter between flocks. Proc. Natl. Poutl. Waste Manage. Symp., Memphis, TN, Pages 177-180. Macklin, K.S., J.B. Hess, S.F. Bilgili and R.A. Norton, 2006. Effects of in-house composting of litter on bacterial levels. J. Appl. Poult. Res. 15:531-537. Macklin, K.S., J.B. Hess and S.F. Bilgili, 2008. In-house composting and its effects on foodborne pathogens. J. Appl. Poult. Res. 17:121-127. Murphy, D.W., 1988. Composting as a dead bird disposal method. Poultry Sci. 67:124.