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United States Department of Agriculture

Agricultural Research Service

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Research Project: Thermal Perches as Cooling Devices for Reducing Heat Stress in Caged Laying Hens

Location: Livestock Behavior Research

Project Number: 5020-32000-013-08-I
Project Type: Interagency Reimbursable Agreement

Start Date: Sep 1, 2013
End Date: Aug 31, 2018

The aim of the proposed work is to develop a novel method to safeguard hen welfare by reducing heat stress (HS) effects. We hypothesize that 1) thermally cooled perches will effectively transfer heat from the hen’s feet and body to the cooled perch via conduction; 2) Thermally cooled perches will improve hen comfort, welfare, and production during the hot summer months; and 3) thermally cooled perches will be a more practical and economically feasible method of cooling hens in enriched cages with lower maintenance requirements than evaporative cooling pads or foggers. Supporting objectives are 1) to determine if thermally cooled perches improve thermal comfort and welfare for caged hens during hot weather, and 2) to conduct an economic analysis of the costs and maintenance of thermally cooled perches. Our short-term goal is to develop a novel method for preventing or reducing HS in caged laying hens. The new method will contribute enormously to bird welfare and safeguard industry profitability. The results will significantly aid with our success in completing our long-term goal, which is to discover the mechanisms of HS; and to deliver reliable measurements as well as to deliver up-to-date recommendations for HS management in farm animals to combat health and production problems induced by global climate changes.

Hens, 17 wk of age, will be randomly assigned to 3 treatments: 1) cages with water cooled galvanized steel circular perches (400 mL/min flow rate chilled to 10o C), 2) cages with ambient air-equilibrated galvanized steel circular perches, and 3) conventional cages without perches. Two trials lasting 12 months will be initiated in early April during each of 2 consecutive years using poultry housing with standard ventilation equipment. The hen housing facility will not be evaporative cooled during the summer to simulate typical housing for laying hens in the Midwest. To simulate a production environment, water cooling in treatment 1 will only be used during hot weather (ambient temperature of 29o C or greater) when hens peak in egg production. If the summer seasons turn out to be mild, then measures will be used to induce heat stress (32o C ambient) without causing mortality by use of mobile heaters. All hens will be evaluated for physical condition (skeletal and foot health and feather quality); biological phenomena (body weight, egg production, egg weight, shell quality, feed efficiency, and necropsies on all mortality); and well–being indicators (body temperature as well as behavioral and endocrine responses). Economic and environmental impacts will be assessed.

Last Modified: 10/19/2017
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