The costs of poultry production are constantly increasing as materials and supply costs continue to rise. According to Drs Brian Fairchild, Mike Czarick and John Worley from the Poultry Science Department at the University of Georgia, utility costs are a significant portion of the expenses that affect the grower's annual net income.

In terms of electricity, incandescent lighting can account for 30 per cent of the electricity used during the summer and 40 per cent during the winter. LED light bulbs are becoming more affordable, and some manufacturers are working on bulbs that can meet the requirements of the poultry industry. The poultry industry needs a bulb that will provide the proper light intensity uniformly at floor level with the ability to be dimmed, as well as have a long life while withstanding the poultry house environment.

Sponsored by the US Poultry and Egg Association (USPOULTRY), a three-year study was conducted on two different broiler farms evaluating three LED light bulbs and comparing them to incandescent (INC) and/or compact fluorescent bulbs (CFL).

At the beginning of the study dimming, light intensity at floor level and power usage characteristics were measured. Every six months, light output was measured to evaluate lumen depreciation. The number of bulbs that were replaced was monitored each flock.

The same dimmer was used in all of the houses but the dimming curves varied greatly. The slope of the light intensity curve of some bulbs dropped quickly as the dimmer setting was reduced while others dimmed slowly. Ideally, the light intensity would decrease linearly.

Compact fluorescent bulbs can be dimmed only so much. If they are dimmed below the manufacturer's suggested voltage level, the life of the CFL bulb is reduced. One reason why CFL bulb life is reduced is that they have a ballast, and the electronics in this ballast can be compromised if the voltage drops below a certain threshold.

LED bulbs do not appear to exhibit this issue. If they are dimmed too low, they just will not produce light. So depending on what the light intensity requirements are during a flock, a producer should determine if the LED bulb they choose can reach the desired lower intensity.

All of the bulbs evaluated in this University of Georgia study exhibited a reduction in light intensity over the duration of the study.

The light intensity depreciation for the LEDs ranged from 11 per cent to 39 per cent while the CFL bulbs and INC bulbs were 6.3 per cent and three per cent, respectively. No LED bulbs were lost during the test period with the exception of Farm 1. There was a manufacturer issue that resulted in 19 per cent of the bulbs failing due to moisture issues. CFL bulb losses ranged from 33 per cent to six per cent for Farms 1 and 2, respectively. Incandescent bulb losses were 38 per cent on Farm 2.

Evaluation of light sources is a long process, stressed Fairchild and colleagues. The driving forces behind using LED and CFL bulbs are energy savings and the diminishing availability of INC bulbs. Most producers would like to know how these energy efficient bulbs are going to hold up in the poultry house environment. So to get a good estimate of the bulb activity over time it requires data from several consecutive flocks.

The other issue with studying bulbs is that manufacturers are constantly striving to make them better, i.e. produce more light with the same wattage, withstanding the environment better and lasting longer. This means that once a study has been conducted on a bulb, it may already be dated because the newer technology is already being sold by distributers.

LED lights offer much promise as a lamp that is long-lasting, easily dimmable and capable of providing the variations in lighting needed for a rapidly changing world of poultry production, concluded the Athens-based researchers.

All LED bulbs are not created equal however, and care must be exercised in choosing a bulb that is economical, reliable and long-lived, they continued. A bulb should be chosen that will provide the desired lighting at floor level, provide it uniformly and with minimal depreciation over time.

The LED bulbs should be able to withstand the dynamic environment, i.e. heat, humidity, dust and cold temperature in between flocks and the occasional house wash-down.

In addition, dimmers should be chosen that will handle the various characteristics of different bulbs. Calibration should be done to make sure that the operator knows what dimmer setting to use in order to achieve the desired lighting level.

February 2015