Design and performance of cooled perches for alternative egg laying production systems

Heat stress in both mechanically and naturally ventilated egg production facilities is a problem for the egg industry. Various means of providing supplemental cooling to hens in facilities are available, including tunnel ventilation to increase convective losses and evaporative cooling from either pads or from misting (lower pressure) or fogging (higher pressure) systems. Evaporative cooling efficiency can be seriously compromised by the challenge of providing cooled air to the birds when in cages and by the development of an axial building temperature gradient as heat loss by birds raises the air temperature. Alternative cooling approaches have included direct wetting of bird surface, and cooled perches have been investigated for broiler chickens and broiler breeders. The provision of a cooled perch in which chilled water is circulated through a conventional galvanized pipe passing through the laying hen cage offers the potential for improved performance during both acute and chronic heat stress events, is amenable to both natural and mechanically ventilated systems, and provides a positive welfare aspect by providing birds with a means to express their natural perching behavior. Challenges with the design and implementation of the system include capital cost and the lack of research data on bird production performance and behavior changes. This paper describes a novel system for testing the feasibility of thermally cooled perches for laying hens.