CHARACTERIZATION OF FRESH POULTRY BEDDING USING DIELECTRIC SPECTROSCOPY AT MICROWAVE FREQUENCIES

Authors: Lewis, Micah; FLOYD, ASHLYN - Hispanic Association Of Colleges & Universities (HACU); Trabelsi, Samir; Oladeinde, Adelumola

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2026
Publication Date: 4/2/2026
Citation: Lewis, M.A., Floyd, A.C., Trabelsi, S., Oladeinde, A.A. 2026. CHARACTERIZATION OF FRESH POULTRY BEDDING USING DIELECTRIC SPECTROSCOPY AT MICROWAVE FREQUENCIES. Journal of the ASABE. 62, 2, 295-301. https://doi.org/10.13031/ja.16574.
DOI: https://doi.org/10.13031/ja.16574

Interpretive Summary: Poultry houses are filled with beddings such as peanut shells, pine shavings, and rice hulls to protect the birds as the flock goes through its life cycle. As the bedding becomes mixed with droppings, feathers, and other byproducts, it becomes referred to as litter. Industry lacks the ability to determine moisture content of the bedding or litter instantaneously with a moisture meter. The standard protocol for moisture determination is 24 hours in a drying oven at a set temperature. The moisture content of the bedding/litter greatly affects the health of the bird. Therefore, it is important to know this parameter quickly to aid in decision making and environment control. Therefore, pine shavings and rice hulls were measured at microwave frequencies to assess the feasibility of moisture content determination for a bulk sample of fresh poultry bedding. Results look promising, and initial tests show calibration errors in moisture content determination < 0.82% moisture content. Such implementation would help the poultry industry in that currently there is no moisture meter for accurate, repeatable measurements.

Technical Abstract: Poultry houses use various materials including peanut shells, pine shavings, and rice hulls as bedding for the birds. Flocks introduce manure and excreta to the bedding, and the material is broken down as the birds walk over it. This causes its properties to change, and it is commonly referred to as poultry litter after this point. As more flocks are introduced to the litter, it breaks down such that it is hard to determine the original bedding material. One important physical property of poultry litter is moisture content, as it greatly affects the health of the birds. However, the low density of the fresh bedding and the changing density of the “used” litter make moisture content detection difficult with capacitance and NIR sensors. There currently isn’t a moisture sensor for repeatable, accurate measurements of fresh or used litter. Therefore, a network analyzer was used to take complex-permittivity measurements on pine shavings and rice hulls at microwave frequencies. The free-space transmission method was used to measure bulk samples varying in moisture content with a volume of 4800 cm3. Measurements were taken at 22°C between 9 and 12 GHz. Dielectric properties were determined and correlated with bedding moisture content by using a density-independent calibration function. The standard error of calibration (SEC) determined for wide moisture range, 11% to 27%, was = 0.82% moisture content wet basis (wb) for all bedding materials. The SEC improved to = 0.43% moisture content for a moisture range 11% to 20%. Results show promise in the application of microwave sensing to the accurate determination of moisture content in fresh poultry bedding.