Agricultural and Biosystems Engineering Publications

Document Type


Publication Version

Published Version

Publication Date


Journal or Book Title

Applied Engineering in Agriculture





First Page


Last Page



Heat and moisture production rates inside animal confinement provide the basis for design and operation of the building ventilation system. This article describes ventilation rate (VR) requirement by a modern high-rise layer (Hy-Line W-36 breed) house based on sensible heat and moisture production rates (SHP, MP) that were newly collected at the bird level or room level – designated as the new data vs. those collected some years ago – designated as the old data. The effects of bird stocking density on VR and balance temperature, tbal (outside temperature below which supplemental heat is needed to maintain the target house temperature) were also examined. The VR values cover an outdoor air temperature range of -25.C to 20.C (-13.F to 68.F) at 5.C (9.F) increments, an outdoor relative humidity (RHo) range of 20% to 70%, and indoor RH (RHi) of 50%, 60%, 70%, or 80%. Use of the old room-level SHP and MP led to a 10% higher VR for temperature control but a 18% lower VR for moisture control, as compared with use of the new data. Similarly, use of the old bird-level SHP and MP led to a 5% higher and a 57% lower VR for temperature and moisture control, respectively. These outcomes arose from the lower SHP but higher MP of modern layers and their housing systems. The results reaffirm the need to use updated room-level SHP and MP in ventilation design and operation of production housing systems. A 31% reduction in cage stocking density by increasing floor space from 355 to 465 cm2/hen (55 to 72 in.2/hen) would reduce VR for temperature control by 6% to 8% and elevate tbal by 1.0.C to 2.4.C (1.8.F to 4.3.F) for a target house temperature of 15.C to 25.C (59.F to77.F) and RHi of 50%. The elevation in tbal can be compensated by temporarily raising RHi setpoint when copying with unusually cold weather.


This article is from Applied Engineering in Agriculture 20, no. 6 (2004): 835–842.



Copyright Owner

American Society of Agricultural Engineers



File Format