Design and performance of an experimental cooled perch system for laying hens

Authors: XIONG, YIJIE - University Of Illinois; GATES, RICHARD - University Of Illinois; HU, JIAYING - Purdue University; HESTER, PATRICIA - Purdue University; Cheng, Heng-Wei

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: his paper summarizes the engineering design of a cooled perch system used in laying hen heat stress investigations. To meet animal welfare demand, egg production is shifting from the conventional cage system to alternative production systems including the enriched colony cages. Installed perches of enriched cages could be modified as cooling devices, to improve hen thermal comfort under heat stress. In this study, chilled water (10 oC) was circulated through the cooling perches during the heat episodes. The outcomes of the system analysis indicate that the cooling system could be an effective cooling method for caged laying hens during hot summer seasons. These results provide a design baseline for egg producers and scientists to further investigate the cooled perch system for improving hen health and welfare during heat exposure.

Technical Abstract: This paper summarizes the engineering design and performance of a cooled perch system used in a multi-year heat stress study (year 2015 and 2016). The cooled system consisted of a three-tier cage unit with galvanized perch pipes forming a complete loop in each tier (top, middle, bottom), a thermal water storage manifold, a water chiller, a control panel with various pumps and thermal sensors. To detect the system’s reliability and repeatability, two cage units (CP-1 and CP-2) were used in this study. Water flow for each loop was controlled by individuated loop pumps, chilled water (10 oC) was circulated from an open thermal storage manifold where the water was constantly circulated and cooled through a water chiller connected with a pump. Each loop pump was thermostatically controlled based on the cage microenvironment temperature. For the system performance evaluation, the water inlet and outlet temperatures, cage air temperatures, and loop water flow rates of each tier were measured during the system operation. Mean water flow rates in year 2015 were 5.19 and 5.45 kg/min for CP-1 and CP-2, then were significantly declined to 3.91 and 4.03 kg/min in year 2016, respectively. The mean loop water temperature rise was approximately 2 oC for both replicates. The mean loop net heat gain of CP-1 and CP-2 ranged from 690 to 850 W and 551 to 1,298 W, respectively, with a significant difference between CP-2 loops (P < 0.0001), indicating there was a discrepancy between the manufacturer’s pump curve and field performance. There was a correlation between room air temperature and the net heat gain for all loops of CP-1 and the top loop of CP-2 (P < 0.0001), suggesting that natural heat convection from ambient air to the pipe was the major contributor to loop heat gain. The average daily net heat gain was approximately 2,334 W/replicate, 256 W/m perch length, or 43.2 W/hen housed. This analysis provides a baseline for future cooled perch system design in commercial settings.