SIOUX FALLS, S.D. (KELO) — The sight of thousands of migrating waterfowl flying across South Dakota, Iowa and Minnesota over the next several weeks can make a poultry producer nervous.

Producers can control security at their facilities to reduce the spread of avian flu (bird flu) but they can’t control the feces dropped by migrating geese and ducks.

Now, with temperatures warming, migration north should increase.

“I’m terrified for it,” said Jason Ramsdell, the general manager for Dakota Layers based in Flandreau. “Twenty-thousand geese flying 1,000 feet above you will drop (feces).”

“They’re going to migrate, we know that,” said Dr. Mendel Miller, the assistant state veterinarian. “We know the wild bird population carries bird flu; it’s been found in other states.”

A map of the four bird migration flyways of North America. U.S. Fish and Wildlife map.

According to wildlife agencies and organizations, spring waterfowl migration is usually from March 15 to May 3. Waterfowl mainly migrate at night with peaks in the middle of the night.

When the waterfowl arrive in a state and cross the state will differ. For example, the Dickinson County Conservation Board in northwest Iowa said “Waterfowl migration can begin as early as late February, and it is fully underway by the first half of March. In Iowa, heavy waterfowl migration is observed the end of March-April.”

They follow four main flyways in North America.

The Central Flyway includes South Dakota, North Dakota, Nebraska and seven other states. Minnesota, Iowa and 12 other states are in the Mississippi Flyway.

The flyways contain prime sites for the poultry industry. Iowa is a top producer of chickens while Minnesota is a top producer of turkeys.

So far, bird flu has been detected in two separately-owned facilities in Charles Mix County in South Dakota, Miller said. The first was detected on March 5. The other was detected on March 11 or 12.

Flocks of about 50,000 each were euthanized at each site, Miller said.

The bird flu crisis of 2015 is a reason why Ramsdell is nervous about this year’s waterfowl migration.

Dakota Layers lost about 1.3 million laying hens and about 10 months of full production, Ramsdell said.

“I don’t think you really recover from that,” Ramsdell said.

The company produces about 400 million eggs a year.

Customers were understanding when bird flu hit in 2015, he said. They know the overall industry was affected.

“We gained most of them back,” Ramsdell said.

The biosecurity measures prompted by bird flu in 2015 remain today, Ramsdell and Miller said.

Stringent measures such as “anybody who goes into a barn needs to shower and change their clothes that we wash in site,” Ramsdell said.

Any allowed entering vehicles need to pass through a tire bath to clean off any material, he said.

Entrance to any facility site is limited, he said.

Those are just some of the biosecurity measures.

“It’s too soon to know (how 2022 will compare to 2015),” Miller said. “The industry is much more aware of it and biosecurity is more of a priority.”

But how does a facility keep poultry safe from what’s dropped from the sky?

Most birds are housed indoors and building openings are limited so that no birds, including waterfowl can enter and to reduce poultry contact with waterfowl feces.

“Sparrows aren’t a health concern but they can pick up a good feather or droppings and use if for a nest,” Ramsdell said.

Nests are destroyed on poultry sites, he said. The company will also disinfect the concrete at the buildings to clean off droppings.

Dakota Layers has an egg-layer site, a poultry site and a free-range poultry farm with about 100,00 birds in the flock, Ramsdell said.

The free-range birds are more at risk of catching bird flu from waterfowl droppings because they have access to grass and pasture, Ramsdell said.

But there is a market demand for such birds and the risk has been reduced by having fewer birds (100,000) than other parts of the operation, he said.

Miller said the poultry infected with bird flu will be genetically tested to help determine the source.