Webinar examines benefits of lighting

Light is one of the six basic requirements to raise healthy broilers. (Photo courtesy University of Georgia)

STATE COLLEGE, Pa. — If done correctly, poultry breeder and pullet producers can benefit from more efficient and effective lighting technology as long as they do their research and math.
When it comes to raising healthy broilers, Dr. Brian D. Fairchild, poultry science professor at the University of Georgia who spoke at a September webinar of the 2020 Pennsylvania Poultry Sales and Service Conference, said it comes down to six basic needs.
They are temperature, air quality, feed, water, protection from disease (a part of the housing, security and vaccination programs) and light, Fairchild said.
What do birds need from the chick stage to market-weight bird age?
There’s research that’s been done, Fairchild said, to show that it’s better to give birds a dark period.
“Give them a light period and give them a dark period,” he said, “because it’s actually been shown to reduce stress, versus putting birds on continuous 24 hours of light, which was done commonly in the ‘70s and ‘80s.”
A bird has a pineal gland that will produce the hormone melatonin, which is only produced in the dark period. And it’s been implicated in a variety of different physiological mechanisms, from regulatory stress, immune (systems) and behavioral issues.
“It’s just natural to be able to give that bird a dark period,” Fairchild said.
Producers can also change the behavior of the birds through light.
Fairchild said: “If we lower the light intensity, we can actually reduce physical activity. This is going to minimalize scratches a lot of times, which hopefully helps lower the incidence of gangrenous dermatitis.”
Lowering the lights can also help with the energy expenditure in terms of kilowatt hours used. A lot of breeder and turkey operations have used lower light intensities to reduce aggressive behavior, the poultry scientist said.
Best sources
A producer has to do his or her research to find which type of bulbs work best and build a lighting system from the best sources.
Increasing amounts of research point to LED lighting, the most cost-efficient for producers on the market. More LED lighting is taking the place of traditional lighting sources.
And how those sources are placed is critical for optimal bird health.
“The light source is the big discussion nowadays,” Fairchild said. “People are starting to move away from incandescent lighting. You still have a lot of people using compact fluorescents, some are still using cold cathode luminescence, and of course LED is probably the upcoming technology that most people are adopting.”
Producers should understand at least a little about lighting and, during the webinar, Fairchild explained some terminology.
Here’s a breakdown of the terms:
• Lumens: a measure of light from the output of the bulb;
• Wattage: the power used to produce that lumen, or light;
• Efficiency: determine this mathematically. Both are on the bulb’s packaging. Simply divide the number of lumens by the number of watts. This will give you a measure of bulb efficiency in lumens per watts;
• Foot-candles: lumens per square foot; and
• Lux: lumens per square meter.
Most of this terminology is printed on most light bulb packages, except for the efficiency, Fairchild said.
Efficiency is “something you will have to calculate, which is really simple to do nowadays,” he said. (See the No. 3 bullet point above.) “You always have a calculator on your phone: You just sit there and compare these efficiencies and try to buy those bulbs that will give you the most lumens for the watt, because that’s what you’re paying for.”
When measuring the light distribution and intensity at the floor level, Fairchild said he uses lux, “because in our meters, I can actually get extra decimal points over reading when I measure in lux than what I do in foot-candles.”
One foot-candle, Fairchild said, equals 10 lux.
There’re really a few things growers need to be concerned with:
• Photo period: How many hours of light per day and how many hours of darkness per day in a 24-hour period?;
• Light intensity: How bright are the lights? How dim are they?
• Wavelength: Light length in nanometers; and
• Spectrum: Marking the color temperature in kelvins, either 2,700k, 3,000k or 5,000k, “which are typically the ranges we see in the lights that are offered for our ag facilities that we have poultry in,” Fairchild said.
What birds see
Fairchild said birds perceive light through their eyes, similar to humans, in terms of rods and cones. They have a different number of cones than we do, which allows them to see further into the ultraviolet part of the spectrum.
They can actually see a wider range of light than what humans can.
However, most light meters that we purchase are usually going to be based on the human visual spectrum. It is hard to find light meters that will measure a wider range, 415 to 700 nanometers.
A blind bird can still perceive daylight through extra-retinal receptors located at the pineal gland at the top of brain, just under the skull. Along with the hypothalamus gland, the pineal gland can be stimulated by light.
For reproduction, birds are seasonal breeders and they are going to tend to breed with longer daylight, Fairchild said. Research indicates that if you have blind birds, you can still get that bird to come into play as long as they had some red light.
Orange and red light are longer wavelengths, which penetrate the skull and stimulate the pineal gland and hypothalamus.
Costs high
A well-lit facility uses a substantial amount of power for heating and lighting.
According to a survey conducted almost a decade ago that is still relevant today, Fairchild said utilities (gas and electricity) account for 60 percent of a typical grower’s annual expense. 
Cold-weather lighting makes up to 40 percent of the electrical costs. In summer, lighting is 30 percent. 
Why the drop in the summer? It’s because a producer starts using more fans, Fairchild said. The electricity used for light generation is less than winter usage.
“If we can figure out ways to do this more economically, that’s a benefit to most farms,” Fairchild said.
Light uniformity
For optimal flock health, it is important that light be distributed evenly and uniformly throughout the facility.
Under grower management guidelines, Fairchild said, “our goal is to see less than a 20-percent difference throughout the house. From the brightest point, under the light bulb, to the darkest point in the house, near the sidewall or corner, we’re trying to see nothing more than 20% or less difference.”
Fairchild said he believes the facility light intensity and uniformity are more important in brooding. Once the birds can identify food and other resources, after brooding, uniformity is not as critical.
“I’m more concerned about getting those birds off to a good start, seeing that nice uniform temperature,” he said.
With LED lighting, it’s important to look at the lumens printed on the package. However, the package doesn’t list the bulb’s efficiency rating.
“You are going to have to do the math to get the efficiency,” Fairchild said.
Some LED lighting, in his measurements, doesn’t vary that much in efficiency. But some are more efficient than others. 
Less energy needed
In an Arkansas study that Fairchild participated in 2012, researchers found that less energy is needed to get comparable wattages from LED lighting, compared to compact fluorescents and incandescent lighting. But producers need to take time to calculate how many watts are used per bulb, how many bulbs are necessary for good uniform lighting, how many hours a day the bulbs will be activated.
Light should be uniform throughout the poultry house. One study looked at LED compared to high incandescent lighting in a 40-foot-wide pullet house, with a low of 0.5 foot-candles at 1.5 feet from the wall to 2.5 foot-candles in the center.
For chickens, lighting should measure at least 3 foot-candles across the house. The variation from the darkest to lightest point should not be greater than 20 percent.
Comparing other factors between incandescent and LED lighting, bird weights and mortality were identical. 
In one study, high-pressure sodium lights in a traditional house at 150 watts and 15,800 lumens was replaced with a LED system.
With the curtain-sided house, the LED system provided more light intensity and uniformity than high-pressure sodium and cut energy costs almost in half.
“If I was going to be doing a new house today, whether its broilers, breeders, whatever, it is going to have three to four rows of LED lights,” Fairchild said. “They are going to be spaced, depending on the bulb, but usually it’s not going to be any further than 15 feet apart.
…Go with the bulb manufacturer to get that optimal light intensity from the bulb. Stick with that 2,700k to 3,000k bulb so that we get more of that red and orange light.”
Ideally, lumens per watt should be 50 kelvins or higher, with broilers 2,700 k to 5,000k and pullets and breeders at 2,700k to 3,000k.
The number of rows necessary depends on the type of bulbs you are using, Fairchild said.
“Most of the manufacturers have the software needed to calculate exactly how many bulbs you need and the spacing for uniform light intensity,” he said.”
And make sure you are getting a more linear dimming curve for LEDs.
As the bulbs age, they start producing less light. It’s a real thing with compact fluorescent lights more so than incandescent. LEDs have a little bit of lumen depreciation.
But because several generations of LED technologies have come and gone, there have been improvements in light depreciation and dimming control.
“If you don’t check that out ahead of time, you might be disappointed about how your dimmer works,” Fairchild said.
The scientist is looking at two commercial LED lighting systems installed in a 54-by-600-foot house. Light measurements will be recorded.
In the end, selecting for LED lighting “needs to be cheap and economical,” Fairchild said. “It needs to have good longevity and it needs to have good efficiency, with the ranges and spectrums we spoke about. I would like to see it waterproof and would like to have a three- to five-year warranty on it. I want it all.”
For more information on the University of Georgia at Athens housing tips website, visit www.poultryventilation.com.