Why important: Caking of litter generally occurs when the moisture content of the litter increases to the point where the litter particles become sticky and cohesive and bind together. When this occurs, the surface of the litter compacts and the chickens are no longer able to incorporate their excreta into the litter.
Moist, sticky and compacted litter on the surface may occur rapidly and for short periods of time (a few hours during the night, or during short periods of rainy or humid weather). The full depth of the litter profile does not need to be wet for caking to commence.
Litter caking causes multiple problems, including increased ammonia and odour emissions. This increased ammonia can cause bird health and welfare issues and impact the health of workers. Increased odour emissions can cause off-site amenity impacts.
Litter conditioning and de-caking can be used to remediate caking.
Outcome: Litter is maintained in a friable state by remediating caking through effective litter conditioning and de-caking practices.
Performance measures: Litter surface is not sticky and compacted and chickens can actively work the litter.
Good housekeeping and effective ventilation, heating and humidity control manage litter moisture and reduce caking.
Best management actions:
Ensure a suitable litter is selected and pre-treated (e.g. chopping/crushing) which exhibits the desired characteristics under operational conditions (Watson & Wiedemann, 2018).
Follow the requirements listed in the In-shed litter management guide to avoid unnecessary litter moisture. This may require regular conditioning to ensure excreta is blended into the litter when chickens fail to achieve this via their movement through the sheds and scratching and digging.
If wet and caked litter cannot be incorporated and/or blended with dry bedding material to produce a dry and friable litter, the most suitable option may be to remove it from sheds and replace it with dry bedding material. Purpose-built machines are available to remove cake while leaving litter in sheds, but small areas of cake can be removed by hand or with manual tools, such as a shovel and wheelbarrow. Removed cake can be utilised in the same way as spent litter (see Spent litter utilisation). Before utilisation, cake should be broken up/pulverised to ensure ease of spreading and to avoid non-uniform application rates on land.
Small areas of wet or caked litter that can be successfully incorporated should be turned to aerate and dry the litter. This can be undertaken using manual tools, an automated rotary hoe, or a tractor fitted with attachments, such as a scarifier/harrow.
