Warm perches: A novel approach for reducing cold stress effect on production, plasma hormones, and immunity in laying hens

Authors: HU, JIAYING - Purdue University; Cheng, Heng-Wei

Submitted to: Journal of Animal Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2021
Publication Date: 5/29/2021
Citation: Hu, J., Cheng, H. 2021. Warm perches: A novel approach for reducing cold stress effect on production, plasma hormones, and immunity in laying hens. Journal of Animal Science and Biotechnology. 100(8). https://doi.org/10.1016/j.psj.2021.101294.
DOI: https://doi.org/10.1016/j.psj.2021.101294

Interpretive Summary: Cold temperature is a common environmental stressor that has a great impact on the poultry industries, inducing pathophysiological stress in birds with profound economic losses. Current methods used for preventing cold stress, such as reducing ventilation and using gas heaters, are facing challenges due to poor indoor air quality and impaired animal and human health. The objective of this study was to determine if perches in enriched cages could be modified as a warming device to improve hen performance and health under cold stress. Hens at 32 weeks of age were randomly assigned to 1 of 3 treatments: cages with warmed perches (WP; perches with circulating water at 30 oC), air perches (AP, regular perches only) or no perches (NP) for a 21-day trial. The room temperature was set at 10 oC during the entire experimental period. The results indicate that the hens that used the warmed perch can maintain their body temperature without increasing feed intake, reducing production performance, and disrupting thyroid function and immunity under cold stress. The findings provide insights for egg producers and animal scientists to develop novel management strategies for improving hen health and welfare during cold seasons.

Technical Abstract: Cold temperature is a common environmental stressor that has a great impact on the poultry industries, inducing pathophysiological stress in birds with profound economic losses. Current methods used for preventing cold stress, such as reducing ventilation and using gas heaters, are facing challenges due to poor indoor air quality and its deleterious effects on bird and caretaker health. The aim of this study was to examine if the newly designed warmed perch system, as a thermal device, can reduce cold stress-associated adverse effects on laying hens. Seventy-two 32-week-old DeKalb hens were randomly assigned to 36 cages arranged to 3 banks. The banks were assigned to 1 of 3 treatments: cages with warmed perches (WP; perches with circulating water at 30 oC), air perches (AP, regular perches only) or no perches (NP) for a 21-day trial. The room temperature was set at 10 oC during the entire experimental period. Rectal temperature and body weight were measured from the same bird of each cage at day 1, 8, 15, and 21 during the cold exposure. Egg production was recorded daily. Feed intake, egg and eggshell quality were determined during the 1st and 3rd week of cold stress. Plasma levels of corticosterone (CORT), thyroid hormones (T3 and T4), interleukin (IL)-6 and IL-10, were determined at day 1 and 21 post initiation of cold exposure. Compared to both AP and NP hens, WP hens were able to maintain their body temperature without increasing feed intake and losing body weight. The eggs laid by WP hens had thicker eggshell during the 3rd week of cold exposure. Warmed perch hens also had a lower thyroxine conversion rate (T3/T4) at day 1, while higher plasma concentrations of IL-6 at day 21. Plasma levels of CORT, T3, and IL-10 were not different among treatments. Our results indicate that the warmed perch system can be used as a novel thermal device for preventing cold stress-induced negative effects on hen health and welfare through regulating innate immunity and metabolic hormonal homeostasis.