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Rodent Damage to Structures

Rodents are small, but the damage they cause to buildings, wiring and feed can be large. They can also carry germs that affect people, so cleanup needs care.

How do rodents damage farm structures?

Rodents gnaw constantly. They chew wood, plastic, insulation and electrical wiring, dig under foundations and tunnel through insulation and feed. Gnawed wiring is a fire risk, and damaged insulation and framing reduce a building's strength.

They also foul feed with droppings and urine, spoil stored crops and can spread illness to people and animals. A small number of animals can become a large problem quickly. Farm buildings are especially attractive because they hold feed, bedding and warmth, and because they often have many small openings around doors, vents and animal pass-throughs. A building that seems tight to people may be wide open to a mouse.

What signs should I look for?

Check where rodents are most likely to nest or travel, especially along walls, in corners and near feed and warmth.

• Droppings, especially near feed and along walls
• Gnaw marks on wood, plastic and wires
• Burrows and holes near foundations
• Greasy rub marks along walls
• Nests of shredded material
• Noises at night in walls and ceilings
• Chewed feed bags and grain

How do I keep rodents out?

Exclusion is the most lasting method. Rodents can squeeze through remarkably small openings, so walk the exterior and interior and close gaps around doors, pipes, vents, cable entries and foundation edges with durable materials that cannot be chewed through.

Keep vegetation, debris and stored materials back from walls, store feed in sturdy containers and clean up spilled grain promptly. Ask your Extension office for building details that suit your region. Pay special attention to places where utilities enter a building, where doors do not meet the floor and where old repairs left gaps. Check again after any renovation, since new work can open new paths.

What control methods are available?

Trapping, sanitation and exclusion work together. Poisons can be effective but they are hazardous to children, pets, livestock and wildlife, and secondary poisoning can occur when other animals eat the poisoned rodent.

Use only products allowed for your situation, and follow the label exactly. The EPA and your state agriculture department can answer questions about legal products and licensing. If you hire help, choose a licensed pest control operator. Snap traps and other mechanical devices should be placed where children, pets and non-target animals cannot reach them, and checked often. Dispose of dead rodents following the guidance of your health department or Extension office.

How do I clean up safely?

Droppings, urine and nesting material can carry germs, and stirring them up can put particles into the air. Do not sweep or vacuum dry droppings, and do not disturb nests in enclosed spaces without guidance.

The CDC provides official guidance on safe cleanup of rodent-infested areas and on diseases linked to rodents. Follow it rather than improvising. If you develop fever, breathing trouble or other symptoms after cleanup, see a health professional and mention the exposure; call 911 for severe breathing difficulty.

What about wiring and fire risk?

If you find chewed wiring, stop using the circuit and call a licensed electrician. Do not repair it yourself and do not cover the damage with tape. Rodent-damaged wiring can spark inside walls, where a fire may not be noticed quickly.

Check electrical equipment, heaters and engines stored for the season, since rodents like to nest in them. Inspect before starting any machine that has been sitting. Equipment is another overlooked hazard. Rodents nest in tractors, combines and stored vehicles, where they can chew hoses and wiring, so look before you start up in spring.

How do I keep up the effort?

Pest control works when it is regular. Put a rodent check on your building walk-through schedule, record what you see and fix new gaps right away.

Teach everyone who works on the farm to report signs early and to keep doors closed and feed covered. A small habit change by many people is often the most effective control. Neighbors may share the same pests, so talking with them about what works can help everyone. Take time to teach younger workers why these habits matter, and thank people who report problems early, because a team that speaks up catches trouble while it is still small and cheap to fix.

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