Litter moisture is one of the most important, if not the most important, litter management parameters at all times of the year. Proper litter moisture is critical to reducing:
- ammonia formation
- bacterial growth
- and litter caking
The result is an environment better for maintaining paw quality and bird health. Maintaining low litter moisture is even more critical in cold winter months when lower ventilation rates are required to conserve heat in poultry houses.
Removing Moisture from Poultry Litter
The only way to remove moisture from poultry litter is by evaporating it into the air and then exhausting the air from the poultry house–a process that requires heat and dry air.
- Heat: Litter must be warm for water to be evaporated from it. Cold litter will not dry out as well as warm litter. The air in the poultry house must also be warm.
- Dry air: Cold air does not hold as much water as warm air. Therefore, maintaining relative humidity below 70% is critical if the air is going to be able to accept the moisture that is evaporating from the litter. If air is saturated (100% relative humidity), it will not accept moisture.
Maintaining the delicate balance between temperature and humidity is important when birds are present, but it must also be done in the downtime between flocks if proper litter moisture is to be achieved–especially in winter.
Failure to maintain optimum environmental conditions during downtime will result in litter that is too high in moisture when it is time to place the next flock, thus likely resulting in high ammonia in the house, high humidity during brooding, and excessive litter caking through the grow-out period.
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Tips for Effective Litter Management Between Flocks in Winter
Keep houses closed. End doors should be immediately closed after birds are caught to conserve heat in the house structure and the litter bed. If end doors are left open in cold weather, all the heat from the house will be lost. Cold air holds less moisture, and cold litter will retain moisture. Only open the end doors while moving equipment in and out of the house for activities such as litter conditioning or application of insecticides and litter amendments. Once this activity is completed, immediately close the doors.
Utilize minimum ventilation. Minimum ventilation should be utilized during downtime to remove moisture and ammonia as it purges from the litter. If the litter is in good condition (not compacted or fine particle size) and is kept warm, this process will naturally occur. A small amount of ventilation is critical to move this moisture and ammonia out of the house and bring in fresh air that can accept more moisture and ammonia. If condensation starts to form on the walls and equipment, then more ventilation is needed. Keeping humidity levels in check will reduce the potential for ammonia-induced corrosion of equipment.
Remove caked litter immediately. Caked litter is 35-60% moisture by weight. The litter bed beneath the caked surface cannot dry out making removal or breaking up of the cake as soon as possible very important. De-caking litter immediately after catch removes large amounts of water from the house and allows the remaining litter to start drying out. If utilizing a litter windrowing program, litter moisture of 30-35% is needed for proper windrow heating. If the loose litter in the house has ample moisture for the windrow heating process, consider removing some of the caked litter before windrow formation to reduce the amount of moisture that must be evaporated once the windrows are leveled.
Use the appropriate litter management technique. De-caking of litter is the best way to reduce litter moisture during downtime since the water contained in the caked litter is physically picked up and hauled out the house. Litter windrowing generally results in litter that is slightly higher in moisture than de-caked litter at chick placement since the caked litter is incorporated into the windrows. Therefore, formation of the windrows as soon as possible after the birds are removed, turning the windrows at least once to aid in the evaporation of water, and adequate time between the leveling of the windrows and placement of the next flock is critical. In wintertime, the number of days between windrow leveling and chick placement will likely need to be greater than in warmer months to allow more time for purging of moisture and ammonia from the litter. Therefore, ample downtime is essential. Do not attempt litter windrowing on a short downtime. At least 14 days of downtime is needed to properly execute litter windrowing, and with extremely wet litter and/or cold weather, several more days should be added.
The use of litter tilling (pulverizing) is not recommended during winter months. Litter tilling does not remove moisture from the house, meaning the moisture in caked litter may be incorporated into the litter bed where it cannot be easily evaporated.
Drinker management. Proper drinker management (height and pressure) is very important during the grow-out period to prevent excessive water spillage into the litter by the birds. Managing drinkers during downtime is also critical. Downtime presents the perfect opportunity to fix leaking regulators or replace leaking nipples. Repairing leaks will go a long way in maintaining proper litter moisture during brooding and equipment maintenance is always easier when no birds are present.
Preheating before chick arrival. While many producers focus on reducing gas usage during winter (for good reason), it’s also the time that preheating of the house and litter is even more critical. Like moisture, ammonia volatilization from the litter is greatly influenced by temperature. Cold litter will retain ammonia, while warm litter will expedite the volatilization of ammonia from the litter. Preheating litter above 80 degrees F will help purge as much ammonia from the litter as possible prior to litter amendment application. Preheating should begin 48 hours prior to chick placement, with PLT application 12 to 24 hours prior to chick placement. Litter preheating will not only extend the effectiveness of the litter amendment, it will also increase chick comfort and thriftiness at placement. Chicks placed on cold litter will lose body heat to the litter, resulting in huddling and decreased feed and water intake. While it is difficult to convince yourself to turn heaters on while no birds are present, the gas used for preheating will more than pay for itself through ammonia reduction and better bird performance.