Rats and mice can be a problem on poultry farms for many different reasons. The damage they cause, and the associated costs, can add up quickly. This is also true for darkling beetles, which are covered in a separate article.

Damage to buildings: With the ability to chew through rubber, aluminum, cinder blocks, plastic, and wool, mice and rats can cause damage to buildings and doors, or to wiring which could result in fires or malfunctioning equipment and alarms.

Destruction of insulation: Compromised insulation reduces energy efficiency and structural integrity.

Consumed feed: A rat can eat 10-20 kgs of feed a year, while a pair of mice may eat 2 kgs. Depending on the cost of feed and the number of rodents present, this can be a major cost from lost feed alone.

Contaminated feed: A rat produces 25,000 droppings a year and a mouse 17,000, providing ample opportunity to contaminate feed and water. A rat can contaminate ten times the amount of feed it eats, with its droppings, urine, and hair.

Disease transmission: Rodents are carriers of at least 45 diseases and pathogens, including salmonellosis and avian influenza. Mice and rats can carry disease-causing organisms on their feet, increasing the likelihood of spread.

Evaluating the problem

A rodent problem is not something to be embarrassed about – it is quite common. Signs of rodent activity include:

• Sounds – such as gnawing, scratching, running, squeaking
• Droppings – on runways, in secluded corners, near feed supplies
• Tracks and rub marks – rodents use the same paths over and over. Look for dust-free tracks along walls or behind storage areas. Look behind vertical pipes near walls for evidence of rub marks from the grease on their fur.
• Burrows – rats burrow in the ground around buildings, with about 7-8cm diameter while mic burrows are smaller at 2-4cm diameter.
• Gnawing marks: Look for wood chips around boards, bins and crates. Fresh gnawing marks in wood will appear light coloured.

Signs without sightings suggest approximately 100 rodents per barn. Frequent nighttime sightings indicate 200-600 rodents, while daytime sightings signal thousands — requiring immediate, aggressive intervention.

Prevention and control strategies

Rodent-proofing farm buildings – proper construction and maintenance help prevent rodents entering the barn. Repair any structural damage and seal holes; mice can squeeze through openings as small as a pencil width. Use coarse steel wool, hardware cloth or sheet metal to cover/fill any entrances; do not use plastic, wood or insulation, as rodents simply gnaw their way through. All places where feed and grain are kept, used, or mixed should be sealed to prevent rodents from entering.

Remove hiding and nesting sites – eliminate anything inside or outside the barn that could be a hiding place such as piled building materials or debris, old feed bags, trash, weeds, etc.

Remove food and water sources – store feed in rodent-proof containers where possible. Eliminate water sources such as leaky taps, open water troughs, sweating pipes and open drains. Reduce feed spillage and immediately dispose of dead animals. Without readily available food and water, populations cannot build.

Traps – both snap traps and multiple-catch traps are an option. It’s important to use the appropriate type of trap depending on whether you have mice or rats. Snap traps should be located close to walls, behind objects, in dark corners, or where you see droppings or gnaw marks, with mouse traps every 2-4m and rat traps every 5-6m. When trapping next to a wall, set the trap at right angles to the wall with the trigger and bait closest to the wall. Orient multiple-catch traps with the entrance hole parallel to the wall. Live traps can work very well near runways used by mice and rats.

Rodenticides – these are toxic to other animals and must be approved by the Pest Management Regulatory Agency of Canada. The approved list of products can be found using an online search, or you can download an app on your phone. Health Canada’s restrictions for using rodenticides on agricultural premises is here.

References:

British Columbia Ministry of Agriculture, 2015. Control of rats and mice on poultry farms. Available online.

Government of British Columbia , 2023. Managing rat and mouse pests. Available online. 

Ontario Ministry of Agriculture, Food, and Agribusiness. Rodent control in livestock and poultry facilities. Updates in 2026. Available online.

Roy Graber for WATTPoultry, 2026. Poultry barn rodents might cost more than you realize. Available online.