On Michael Christensen's Flying C Farms near Sleepy Eye, toms — male turkeys that can reach 50 pounds each — can get pretty feisty, injuring themselves when they get riled up.
But they've been better behaved since Christensen installed special LED light bulbs in his turkey barns about five years ago.
"This seems to calm them more," he says.
Christensen got his lights from Once, a Plymouth, Minn., firm that makes bulbs that generate light that seems natural to chickens, turkeys, pigs and other livestock. And that light, the company says, means happier, healthier, and bigger animals.
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"The calmer bird is going to put on weight better," says Christensen, who raises some 80,000 turkeys a year.
Christensen turns on the lights when there's not enough sun to light his turkey barns. He describes the bulbs as giving off a dull white light. But turkeys see different wavelengths of light than humans do. These bulbs seem more natural to them than standard indoor lighting. And if they help the birds add just a half pound each they add to Christensen's bottom line.
"If you can credit that to lighting, it's a pretty good payback," Christensen said. "If I was to build another barn, I would put these in right away."
The energy-efficient bulbs also reduce Christensen's electric bill and last longer than the lights he had before.
Once CEO Zdenko Grajcar says the company can tune lighting for a variety of animals, ranging from foul to fish.
"We research how that animal sees," he says, "and what individual colors are stimulating in the animals. And we create a light source mimicking that."
The bulbs also can be adjusted to mimic sunrises and sunsets or even seasons, making it seem like summer year-round if a farmer wishes.
Grajcar studied nuclear physics and astronomy in his native Slovakia. His company has some 160 patents issued or pending. Once's bulbs cost up to $45 each. The company won't disclose its sales but counts about 800 customers, including the poultry giant, Perdue. Grajcar estimates the worldwide market for animal lighting is billions of dollars a year.
And he says the technology can be powerful. Grajcar says it can even manipulate the sex of an embryo in an incubating egg.
"We can decide that we will have all of the animals female or all of the animals male, by light," he said.
Grajcar says that application is still in its early stages., but university researchers aren't disputing the underlying science.
"When the birds are young there's more red spectrum so they're a little more stimulated," said Susan Watkins, a professor at the University of Arkansas' Center of Excellence for Poultry Science. "Then they can dim it down to a more blue spectrum. Some of the literature out there supports that the blue spectrum tends to allow the birds to grow more efficiently, help them to be more calm."
Skeptics should keep in mind that birds and other animals don't see things the way humans do, says Texas A&M University poultry specialist Gregory Archer.
"Think of an incandescent light bulb, you see yellow. A chicken sees that basically as a red light bulb. We see it as yellow. They see it as red."
And if they're seeing red, it can affect their behavior — and a farmer may be clueless that the bulbs in a barn could well be affecting the bottom line. But Archer says light is increasingly recognized as an important factor in raising livestock.
"With the new technologies out there, it's kind of becoming evident that you can actually improve things a lot more than you used to be able to," he said.