University of Missouri Extension

G7030, Reviewed October 1993

Fly Control in Caged Layer Buildings

Robert D. Hall and Flernoy G. Jones
Department of Entomology

House flies, soldier flies and other non-biting flies can and often do become a problem in poultry buildings. They do not bite or feed on the birds but may carry pathogens because of their habit of feeding on manure, dead birds and other waste materials.

Poultry manure is an excellent development material for fly larvae. Caged layer operations concentrate a large amount of manure in a relatively small area and therefore create an ideal situation for producing many flies. Flies and odor coming from poorly managed buildings may result in legal action against the producer.

This guide gives recommendations for controlling flies only in caged layer operations where the birds are not in contact with the floor or litter. Properly managed floor operations seldom have a fly problem.


Effective and economical fly control depends on:


The first, most important step in fly control is prompt and regular removal of waste material where flies breed. Flies lay eggs on wet, decaying material. This includes waste feed, broken eggs and dead birds. The maggots that hatch from these eggs cannot develop in manure or other dry materials.

Keep droppings dry. Repair water leaks, both in water supply lines and building roofs. Soldier fly infestations usually start around the outside of open buildings where rain and snow have blown onto the manure and made it wet.

The caged layer operator has two options available when considering the frequency of manure removal:

The manure that is removed should be thinly spread in fields, not piled outside the buildings.

If good sanitation practices are followed, less insecticide will be needed and that used will be more effective.

Fly control in open houses

Acceptable fly control in open houses requires strict attention to sanitation and manure management, supplemented with the use of insecticides as baits, residual sprays and spot treatment of manure for maggot control.

Baits consist of an insecticide and an attractant, which serves to draw flies to the insecticide. Start spreading the bait as soon as flies begin to be numerous. Place bait where flies congregate during the day — window ledges, doorways, on the floor between cages, etc.

During the first four or five days, scatter dry bait heavily enough that it can be seen. Continue to put out bait each day for the next week, using smaller amounts than for the first application. After the first 10 days, apply bait every two to four days to those places where the most flies were killed during the initial baiting.

To make a liquid bait, mix the proper amount of insecticide with water and add sugar, corn syrup or molasses. Follow the directions on the container label. Use a sprinkling can to spread the bait on the floor. On a dirt floor or where the floor is dirty, apply the bait on pieces of burlap, cardboard, etc. Apply new, fresh bait every two to four days.

Continue to use bait regularly during the summer. Don't stop as soon as fly numbers are knocked down. If you do and the numbers build up, you will have to start all over again with the heavy initial baiting.

Recommended ready-to-use dry baits

Recommended liquid baits (must be prepared by user)


Don't place baits where birds may come in direct contact with the material. Don't contaminate feed, water, utensils or eggs.

Residual sprays leave a deposit of insecticide that the fly contacts when it lands on the treated surface. Residual sprays will remain effective for a few days up to several weeks. Apply the first spray around doors and windows, walls, ceilings and rafters in late spring or early summer as soon as flies begin to be a problem. Repeat applications as needed. Apply 1 gallon of spray per 500 to 1,000 square feet of surface. On unfinished wood, brick or concrete surfaces, wettable powder formulations will give longer lasting control than emulsifiable concentrates.

Recommended residual sprays


Remove birds and eggs before applying dimethoate. Don't apply fenthion, permethrin, Rabon or ronnel directly onto birds. Avoid application where drift or droplets contact birds; this may necessitate covering the cages during the application of fenthion, permethrin, Rabon or ronnel. Cover feed and water troughs before spraying with any insecticide.

House fly resistance to permethrin
In some areas of Missouri, house flies have become resistant to residual sprays of permethrin. Rates that have good control the previous season often fail suddenly when reapplied in the spring. If this happens, do not continue permethrin use. Instead, apply an organophosphorous insecticide as a residual surface treatment. Ensure adequate sanitation and consider using bait and fogs to reduce populations of adult flies.

Maggot control
Maggots should not develop in manure that is kept dry. If the manure becomes wet, correct the cause of the moisture. If maggots develop in the wet manure, make spot applications of one of the recommended maggot sprays to the infested manure. Apply as a coarse spray or with a sprinkling can. Apply approximately 1 gallon per 100 square feet of surface area.

Recommended maggot sprays

  1. Dimethoate
    Use 1 pint of 23.4 percent dimethoate emulsifiable concentrate in 2-1/2 gallons of water.
  2. Rabon
    Use 5 tablespoons of 50 percent Rabon wettable powder in 1 gallon of water.


Don't apply where birds may come in contact with the treated manure.

Feed-through fly control
Insecticide may be applied to the droppings of caged laying hens by incorporation in the feed. This ensures even distribution in the droppings and is very labor-economical. An adequate batch mill is required for even distribution of the material in large quantities of feed.

Recommended feed-through
Use cyromazine (Larvadex) 0.3 percent pre-mix at the rate of 1 pound per ton of finished feed (final rate of 1.5 parts per million) for control of house flies. Feed continually until house fly larval development is suppressed, then feed every other week for the remainder of the fly season. Do not cease sanitary practices and scheduled removal of the droppings. Spot-treat any maggot infestations with a maggot spray as described above.

Fly control in closed houses

Flies should not become a problem in closed houses if good sanitation practices are followed and all openings are kept screened. Screen air inlets with fly screening and keep good springs on screen doors.

If a fly problem does develop in a closed house, apply a fog of insecticide to knock down the adult population.

Recommended fog insecticides

Make the application in early morning before flies become active or late afternoon after flies go to roost. Turn off fans; make fog application; then turn fans on. Direct fog toward ceiling for best results.

As a supplemental treatment, use baits as described under the "Fly control in open houses" section. Apply around doorways and on the walkway floor between cages.


Don't place baits where birds may come in direct contact with the material. Don't contaminate feed, water, utensils or eggs.

Maggot control
If maggots develop in the manure under the cages, follow the directions in the "Fly control in open houses" section.

Feed-through fly control
Use cytomazine as described in the "Fly control in open houses" section.

Residual sprays
Applications of a residual spray on outside surfaces near doors and other openings will aid in reducing the number of flies that enter the building. Follow the directions and restrictions as given in the "Fly control in open houses" section.

General precautions
Don't apply non-registered materials directly to poultry or within poultry houses. To do so may cause the meat or eggs to become contaminated and unsalable. Be sure to read and follow the safety precautions given on the label of the container.

Missouri insect control recommendations are revised annually and are subject to possible change during the season. No discrimination is intended, and no endorsement is implied.
G7030 Fly Control in Caged Layer Buildings | University of Missouri Extension

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