Recommendations for Minimizing Heat Stress in Caged Layers

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  • Provide a minimum of 3.5 L/s (7 cfm) per bird of exhaust fan capacity. This may require two air changes per minute in a high-density cage house.
  • Air inlets should be properly adjusted, especially when using baffle boards, to achieve a uniform flow of air throughout the length of the building. Buildings with more than three rows of cages require inlets on both sides.
  • Assess air movement in the barn with the use of a static pressure monitor (manometer). Problem barns should be smoke tested. Consult your local agricultural engineer for assessment of your ventilation system.
  • Proper maintenance of exhaust fans requires inspection and cleaning of shutters, adjusting belts, and proper hood placement to protect against wind gusts. Baffles, intakes, thermostats, motors, shutters and hoods should be cleaned and adjusted on a regular basis. Up to a 50% loss of efficiency may result from poor maintenance of ventilation equipment. All electrical equipment should be routinely inspected by your electrical contractor.
  • Check belt drive fans for belt alignment and correct belt tension. Both too much and too little tension can reduce fan performance and cause early belt failure. In addition, too much tension can cause bearing failure while too little tension can cause drive sheave failure.
  • Stand-by generators and alarm systems should be properly maintained and tested monthly with results recorded in a log book. High-low temperature alarm systems should be set in the sensitive range so that the farm manager can react to elevated temperatures quickly.
  • Foggers and misters properly installed and maintained could reduce losses due to heat stress provided air changes occur as described in text.
  • Buildings should be properly insulated. New buildings should have R20 for walls and R28 for ceilings to reduce radiant heat gain. Provide screened or perforated soffits and ridge ventilators for attic ventilation.
  • Grass and vegetation should be mowed regularly especially on the air-inlet side of the building.
  • Wide open doors and inlets will cause the static pressure (negative pressure) to drop, resulting in a loss of air speed. Air speed aids in heat loss through convection.


  • Monitor water consumption. Ten thousand layers in full production will consume 2,000 L per day during normal environmental temperatures. Above 32°C water consumption can increase up to 50% . Ensure that water pipes are properly sized to prevent water shortages bearing in mind peak demand.
  • Water system management must ensure adequate pres-sure and volume of cool water throughout the length of the building. Pressure regulators and water filters need to be serviced regularly. It is advisable to flush water lines prior to anticipated heat periods. Check water flow and temperature gauges at the far ends of the building during the warmest part of the day.
  • Water treatment with polyphosphates and/or chlorine may be necessary to prevent buildup of iron-mush bacteria and mineral deposits.
  • In most cases, water quality has a greater effect on equipment then upon the direct health of the birds.

Feed and Lighting

  • During hot weather it is extremely important to monitor feed consumption daily, to ensure an adequate intake of nutrients on a per bird basis. This is particularly important for the 24 to 30 week old pullet. Special feed formulations do exist for summer feeding. Consult your feed company for details. Stirring existing feed within the trough by operating feed lines between feedings helps increase consumption. Running the feeders early in the morning will stimulate feed consumption during the cooler hours of the day.
  • The lighting system time clocks should be set to come on in the early morning, cooler hours, i.e. before 6:00 a.m.

Egg Quality

Eggs should be collected more often and cooled down immediately in a properly equipped egg storage room to maintain internal egg quality.

Extra care should be taken in handling the eggs in hot weather, due to reduced shell quality.

In shallow pit operations producing liquid manure, arrange clean-out immediately following egg pick up, to minimize the effect of splashing.

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