Cold Weather Ventilation & Moisture Control of Poultry Houses
Maintaining minimum ventilation and proper moisture control are essential for poultry house operation in cold weather. Learn tips for preparing houses for efficient and effective cold weather management.
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Block the Correct Vents
One of the most common minimum ventilation mistakes made by producers during brooding is not blocking vents. The perimeter air inlets (vents or baffles) on the non-brooding end (off end or grow-out end) should be blocked off during brooding to ensure that minimum ventilation air enters the barn in the brooding chamber first and targets the ceiling peak.
Air that enters and exits the non-brooding area of the house does not count toward minimum ventilation. Only air that enters the bird area counts. Thus, air allowed to enter and exit the non-brooding ends and bypass the brooding chamber should be deducted from minimum ventilation calculations. Using all the perimeter inlets in the barn during minimum ventilation without compensating for this air bypass could be a mistake.
Learn MoreAn example where 50 percent of the ventilation air is bypassing the brooding chamber. Notice that one fan is ventilating the brooding chamber and the other is ventilating the non-brooding chamber. If the producer is counting both fans toward minimum ventilation, the air exchange in the brooding chamber will not be enough, and the results will likely be undesirable. To compensate for the off-chamber bypass ventilation, minimum ventilation run time of 60 seconds ON (240 seconds OFF) would need to be increased to 120 seconds ON (180 seconds OFF). This would be a good starting point.
In this case, improving brood chamber air exchange is a matter of either adding the additional time or closing the non-brooding area vents. It is acceptable to open some vents in the back of the house, but keep in mind that air does not count toward minimum ventilation. We are looking for a vent opening of about 1 1⁄2 to 2 inches. For some houses, this cannot be achieved without blocking selected vents to get the proper opening.
Proper inlet door opening is very important for bird comfort, moisture removal, and uniform floor temperatures. This opening must be routinely checked and adjusted when necessary for optimum minimum ventilation performance.
Following are tips on vent management and moisture control:
Check for missing vent door insulation. All perimeter vents must be fully insulated so that they tightly close when not in use. Any missing insulation will likely be the source of a cold-air leak that throws air directly to the floor. This air works against litter drying (incomplete pass), drafts chicks in the vicinity, causes uneven floor temperatures, and causes excessive heater run time. If the insulation cannot be repaired, it is time to replace the door.
The insulation in figure 2 has been damaged by rodents. The door opens and shuts but does not seal when closed and is leaking on three sides. It is overdue for repair or replacement. This often is found on inlets located closest to the feed cross-fill entrance to the house, where rodents have direct access to the house wall and attic space.
The vent in figure 3 is another major source of air leakage. The leakage is made worse by the insulation that is settling out of the door and getting wedged between the door and frame. The metal door appears to be in good shape, so the recommendation is to replace the insulation on this door.
shutters, about 2 1⁄2 to 3 inches of dust settled in the bottom of the light traps and framing, about 1 to 1 1⁄2 inches of dust in the fan housing, and totally dust-covered light traps.
Check belts. All minimum ventilation fan belts should be new or like new. Compare used belts to new ones or measure them to determine if they are adequate. Don’t assume they are good—verify. If you can hear the fan squeal on the motor pulley, fix the fan.
Test tensioners. All fan tensioners must be lubricated, exercised, and tested for worn or dry bearings. If the bearing is frozen and the belt is cutting into the pulley, replace it with a new one. Most tensioners freeze up in the relaxed position, so make sure the tensioner is placing some stretch force on the belt.
The fan in figure 6 was still in operation, and the belt was cutting into the plastic pulley when the tensioner pulley failed. The squealing noise due to the friction between the belt and plastic pulley could be heard from outside the house.
Maintain bearings. All bearings must be greased or replaced. Don’t leave a dry bearing on a fan. Get it fixed.
Read also: Need for holistic approach to poultry gut health
Conclusion
It is general practice to maintain house relative humidity between 50 and 70 percent during cold weather. Check humidity first thing in the morning for best results, and make adjustments. Blocking the correct vents forces air to target the ceiling peak (or as close as possible) so that the incoming air can acclimate, mix, and provide fresh air to the house and birds. This is how moisture is removed from the house. You want this to happen as evenly down the house as possible. Some variations to this are acceptable, and this will take some experimenting and adjusting to make it work properly for each house and farm.
You need every possible cubic foot per minute (CFM) of each fan used for minimum ventilation to work at maximum capacity in every cycle. Anything less than 100 percent is a loss in adequate air exchange and static pressure ability. Any inadequacy in fan performance will have to be made up with additional run time. Don’t forget the importance of house tightness and the use of stirring fans during cold weather.
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