The fastest way to stop flies is to remove what attracts them
Flies breed in wet manure and spilled feed. If your coop has either one, no amount of trapping or spraying will stop them for long. The real solution is daily cleanup: remove wet bedding, rake out manure at least three times a week, and sweep up spilled grain before dark. A coop that stays dry and clean will have far fewer flies than one that is treated with insecticide but left filthy.
The second step is to make the coop less hospitable to the flies that do arrive. Flies need moisture to breed. If you use deep litter (letting manure pile up under fresh bedding), switch to shallow bedding that you turn over or replace more often. Add a roof overhang or shade cloth so rain does not soak the bedding. If you have a waterer that leaks or spills, move it to a concrete pad or replace it with a nipple drinker that wastes less water.
Key Takeaways
- Wet manure and spilled feed are what flies need to breed, so removing these daily stops the problem at the source better than any trap or spray.
- Shallow bedding that you replace or turn regularly dries faster than deep litter and cuts fly breeding sites by half.
- Shade cloth, roof overhangs, and nipple drinkers reduce moisture in the coop without extra work.
- Fly traps and predators like guinea fowl or parasitic wasps work best as a second layer after you have cleaned up the coop itself.
- Manure piles outside the coop should be covered or turned weekly, because they are where most flies breed if the coop is clean.
Bedding choices that dry faster and breed fewer flies
Deep litter — the practice of layering fresh bedding over old manure — saves work but creates a fly breeding ground. The bottom layers stay wet and warm, perfect for fly larvae. If you use deep litter now, switch to a shallower system: add 2 to 3 inches of fresh bedding, then remove the top 4 to 6 inches once or twice a week and replace it. This keeps the coop drier and gives flies fewer days to lay eggs before you remove the bedding.
Pine shavings, sand, and straw all work, but sand dries fastest and is easiest to rake. Shavings hold moisture longer but are cheaper. Avoid hay, which molds quickly and holds water. Whatever you choose, turn it with a rake or shovel at least twice a week — this breaks up clumps, lets air reach the bottom, and exposes fly eggs and larvae to light and drying.
If you have the space, keep a separate manure pile outside the coop and cover it with a tarp or turn it weekly. Flies will still breed there, but at least they are not breeding inside where your birds live and eat.
Water management and feed storage to cut moisture
A leaking waterer can soak an entire corner of the coop. Check your waterer daily for drips and cracks. If it leaks, replace it or move it to a concrete pad so water drains away instead of soaking into bedding. Nipple drinkers waste almost no water and are worth the switch if you have more than a few birds.
Spilled feed attracts flies and rats. Use a feeder with a lip or tray to catch spillage, and sweep under it every evening. Do not leave feed out overnight. If you scatter grain on the ground, do it in the morning and remove what is not eaten by dusk. Wet feed spoils fast and breeds flies, so do not mix grain with water unless the birds will finish it in an hour.
Traps and baits that work after cleanup
Once you have removed the breeding sites, traps become useful. Sticky traps hung near the coop entrance catch adult flies before they lay eggs. Yellow sticky traps work better than other colors for most fly species. Replace them weekly or when they are covered.
Fly baits and granules work if you scatter them in dry spots where birds cannot reach them — under the coop, in a corner behind a feeder, or in a separate trap box. These baits kill adult flies but do not stop breeding, so they are a temporary measure while you fix the moisture and manure problem.
Do not spray insecticide inside the coop where birds eat and drink. The chemicals can poison your flock or contaminate eggs. If you must use a spray, use it outside the coop or in the evening after birds have roosted, and let it dry completely before birds return.
Natural predators and parasites that eat fly larvae
Guinea fowl eat thousands of insects a day, including fly larvae in manure. If you have space and your local rules allow it, a few guinea fowl in or near the chicken yard will cut flies dramatically. They are louder than chickens and need their own shelter, but they are effective and require no chemicals.
Parasitic wasps (tiny, harmless to humans) lay eggs in fly pupae, killing them before they become adults. You can buy them online and release them in the coop or manure pile. They work best in warm weather and need to be reintroduced every few weeks because they do not stay in one place. They are a good second layer of defense after you have cleaned up the coop.
Ventilation and sunlight to keep bedding dry
A coop with poor airflow stays damp even if you clean it regularly. Open windows or vents on opposite sides of the coop to create cross-ventilation. In warm months, leave doors and windows open during the day. Sunlight kills fly eggs and larvae, so if your coop gets direct sun in the morning, use that to your advantage — rake bedding into sunny spots to dry it out.
In winter, ventilation matters less because flies are dormant, but moisture still causes mold and disease. Aim for airflow without drafts: vents high on the walls let warm, moist air escape without creating wind at bird level.
Seasonal timing and when flies are worst
Flies breed fastest in warm weather, usually from late spring through early fall. In these months, clean more often — every other day instead of three times a week. In winter, fly populations drop naturally, but do not skip cleaning because wet bedding still causes disease.
Start your prevention routine before flies arrive. In spring, before temperatures rise, switch to shallow bedding, fix any water leaks, and clean out the coop thoroughly. This head start stops the population from exploding in summer.
Frequently Asked Questions
Can I use diatomaceous earth in the coop to kill flies?
Food-grade diatomaceous earth kills insects by drying out their exoskeletons, but it only works on dry surfaces. Dust it in dry bedding corners and under feeders, not on wet manure. It is less effective than cleaning and drying the coop, and birds should not breathe large amounts of the dust. Use it as a second step, not a replacement for removing wet bedding.
Will fly paper or sticky traps hurt my chickens?
Sticky traps are safe if hung high enough that birds cannot reach them — above head height or in corners. Hang them near the coop entrance where flies enter, not where birds roost or eat. Check them weekly and replace when covered.
How often should I clean the coop to stop flies?
In warm months, remove wet bedding at least three times a week and rake the rest to dry it. In cool months, once a week is usually enough. Daily spot-cleaning of wet corners and spilled feed helps more than a single big cleaning once a week.
Do fans help keep flies out of the coop?
Fans dry bedding and create airflow that flies dislike, but they do not stop breeding in wet manure. A fan is useful as part of your ventilation system, especially in humid climates, but it is not a substitute for removing wet bedding and manure.
What if I have a large flock and cannot clean the coop that often?
Use sand instead of shavings — it dries faster and is easier to rake. Keep a separate manure pile outside the coop and turn it weekly. Add guinea fowl or parasitic wasps to handle the flies you cannot prevent. These steps together reduce the cleaning burden while still controlling flies.