Fly Control on Small Farms

Why do flies become such a problem around animals?

Flies lay eggs in moist organic material: manure, wet bedding, spilled feed, rotting hay and mud mixed with waste. Warm weather shortens the time from egg to adult, so a small damp corner can produce a surprising number of flies in a short stretch.

Heavy fly pressure is more than a nuisance. Animals that are constantly bothered stamp, bunch up, eat less and lose condition, and flies can irritate eyes and wounds. Knowing where they breed tells you where to spend your effort.

Different fly species behave differently. Some breed in manure, some bother animals' faces and eyes, and some bite. Ask your extension office to help you identify what you have, because the control that suits one may do little for another.

Where should I look for breeding spots?

Walk the farm with the question, where is it wet and where is it old? Check under feeders and waterers, along fence lines where manure collects, in corners of stalls, around calf or kid pens, beside the compost pile and under tarps where moisture sits.

Leaking water troughs and poor drainage are common culprits. A dry spot with fresh manure is much less attractive to flies than a damp one with old buildup.

• Leaky waterers and overflow areas
• Old bedding packed in corners
• Spilled feed and wet hay under feeders
• Manure piles near animal housing
• Low spots where water stands after rain

How does sanitation reduce flies?

Sanitation is the foundation. Remove manure and soiled bedding on a regular schedule, and do not let it sit against walls or fences. Spread thin where it can dry, or compost it properly and keep the pile away from animal areas.

Fix drainage and leaks, keep bedding dry, and feed in a way that keeps spills to a minimum. Even small improvements, done consistently through the warm season, cut breeding more than occasional big cleanups.

What other non-chemical options exist?

Traps and sticky surfaces can reduce the numbers of adult flies, though they work best alongside sanitation. Good airflow in barns helps, since flies prefer still air. Fans in the right spot can make a real difference where animals rest.

Some small farms use natural enemies that attack fly pupae, and chickens or ducks that scratch through manure can disturb breeding, though birds bring their own manure and management needs. Ask your extension office what works in your climate and whether a supplier of beneficial insects is reputable.

Whatever you try, give it a fair trial and note the result. Count flies on a trap or a fixed surface weekly and see whether numbers fall after a change.

What about sprays, pour-ons and feed additives?

Any product meant to kill flies must be used exactly as its label directs, for the species and use listed, and the label is the law. This guide does not recommend products or amounts. Some products are not allowed near certain animals, milk, eggs or meat, and some harm beneficial insects, bees and water life.

If you plan to use anything chemical, ask your veterinarian or your extension office which options suit your animals and what withdrawal or safety rules apply. Rotating approaches and relying on sanitation first also slows resistance in fly populations.

How do I build a simple yearly fly plan?

Start before the heat. In early spring, clean out winter bedding, fix leaks, improve drainage and check your equipment. Through the warm months, pick a regular cleaning day and keep a short log of what you did and how bad the flies were.

At the end of the season, note which spots stayed troublesome. Next year, tackle those first. A plan you can repeat every week beats a complicated one you drop in July.

What helps animals cope while flies are present?

Even good control will not eliminate every fly, so give animals ways to cope. Shade and shelter let them get away from the worst of it, and a breeze through open-sided shelters helps. Wet, muddy areas draw flies, so offer dry resting ground.

Check animals for sores, wounds and irritated eyes, since flies are drawn to them. A wound that attracts flies needs a veterinarian's attention rather than home treatment. Keep fresh water available and keep an eye on feed intake, since animals under constant fly pressure may eat less and lose condition.

• Provide shade and a breezy shelter
• Keep animals off wet, muddy ground
• Look over eyes, wounds and sores daily
• Call your vet about any wound that draws flies

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.