Air speed and bird performance (Poultry Specialist)
Memorial Day is just around the corner which means hot summer weather is soon to come.
It is important to be properly prepared for the hot summer weather ahead of us.
Probably one of the most important factors to address are tunnel fans.
Time and time again, I hear that air speed is king when it comes to sufficiently cooling birds.
So how important is air speed when it comes to bird performance?
A study published in 2003 by researchers in Mississippi compared the performance of birds exposed to a wind tunnel with approximately 400 feet per minute air speed to the performance of birds exposed to a wind tunnel with approximately 600 feet per minute air speed.
The body weight gain of broilers between 5-6 (1.43 pounds) and 6-7 weeks of age (1.30 pounds) exposed to the 600 feet per minute air velocity was higher compared to the body weight gain of 5-6 (1.36 pounds) and 6-7 week old broilers (1.11 pounds) raised in the 400 feet per minute air velocity environment.
Similar improvements were reported with broiler feed efficiency.
Tunnel fans are the primary means in which birds are kept comfortable during hot summer weather.
Tunnel ventilated houses have been constructed to have enough tunnel fan capacity to produce a wind speed of at least 600 feet per minute.
The ability to keep birds cool in a house depends on keeping all of these tunnel fans properly maintained.
A large part of fan performance is attributed to its belt.
When a fan belt is loose, the fan blade cannot spin at its maximum revolutions per minute.
It also adds wear to the pulley. A properly installed fan belt should sit flush with or slightly above the top of the pulley.
It is probably a good idea to routinely replace fan belts at least one or two times a year.
Dirty fan blades and shutters can also reduce fan efficiency. It has been reported that dirty shutters can reduce the airflow of a fan by as much as 30 percent.
Besides visually inspecting belts and pulleys, University of Georgia researchers recommend using a laser tachometer.
A laser tachometer when pointed toward a single rotating blade can provide a quick measurement of the speed of the rotation of a fan blade.
A fan count per minute will be displayed on the tachometer, and with this information can be used to determine the fan prop speed.
When the fan blade count per minute value is multiplied by the number of fan blades it will give you the fan prop speed.
This value can be compared to the proper fan prop speed determined by the fan manufacturer. University of Georgia recommends if that value measured by the laser tachometer is more than 5-percent slower than the manufacturer specification, then the fan belt should be replaced.
If the fan prop speed remains too slow after the belt is replaced, the fan motor pulley likely needs to be replaced.
Seasonal changes always present some challenges for poultry growers.
As warm weather approaches it is important for growers to evaluate their tunnel fans to ensure they are working properly.
Any needed repairs should be timely and in advance of hot weather and older birds.
It may also be a good idea to have extra belts and parts on hand in case they are needed for a quick fan repair.
Additionally, growers may want to have their generators serviced, alarms tested and alarm batteries replaced.
Remember as the saying goes, “Thorough preparation makes its own luck.”
1-800-634-5021 410-822-3965 Fax- 410-822-5068
P.O. Box 2026 Easton, MD 21601-8925