Canadian Poultry Magazine

Preventing Rodents

By Marc Lalonde biosecurity Technician Eastern Canada and Dave Van Walleghem biosecurity technician Western Canada Vétoquinol Canada Inc.   

Features Barn Management Production Pests Poultry Production Production Protection

Tips on how to keep rodents from eating away at bottom line

Rodents in a farm environment are a fact of life, but not all of us realize the full extent of the financial and health threat they pose. Producers need to act quickly when they face a rodent infestation, because it is significantly easier to deal with the first pair coming into the barn rather than the 500 at the end of the year.

A barn provides an ideal home for rodents as they can have access to all the food and water they need, protection from harsh weather conditions and from outside predators.

Eating up profit
On the farm, your feed represents an easy all-you-can-eat buffet for rodents, as they eat and contaminate livestock feed supplies. The average mouse will consume two to four grams of feed a day, while a rat will eat up to 28 grams Although it does not seem like much, it can represent between 730 and 1460 grams for one mouse and 10 kilograms for one rat over just one year – and there is always more than one rodent in the barn! You may be buying extra feed just for the rodents without even realising it, which can directly affect your profitability.


Rodents can also cause damage to buildings. They gnaw at wood, water pipes and electrical wires, which can cause fires, equipment malfunction, power outages, water leakage and expensive structural damage. They also destroy building insulation, resulting in heat loss and increased energy and feed costs, all of which can also have a significant impact of the farm’s bottom line.

A health threat
Rats and mice can be responsible for transmitting diseases. They contaminate feed supplies with viruses and bacteria that are often detrimental to the health of livestock. Rodents are known to transmit such diseases as salmonella, plague, toxoplasmosis, leptospirosis, rickettsia and pox. They can also carry fleas, ticks and other parasites, which can potentially introduce additional diseases into your herd or flock. As well, rodents represent a food source that can attract predatory animals such as foxes, skunks and cats that, in turn, may pose another biosecurity risk to your herd.

With the Canadian Quality Assurance Program regulations, health safety considerations and economic pressures, one can’t just throw rodenticides into the barn and hope they work. 

Effective control of rodents involves three steps: 1) sanitation, 2) rodent-proof construction and 3) population reduction.

Although good sanitation will seldom eliminate rodents, it will help in controlling them. Conversely, poor sanitation is sure to attract mice and rats and allow them to thrive in greater abundance.

  • Keep barn premises and
  • surroundings clean.
  • Remove all sources of water.  
  • Remove manure and feed spillage as often as possible.
  • Thoroughly clean and disinfect the barn on a regular basis.

Rodent-proof construction
A lasting form of rodent control is to “build them out” by eliminating all openings through which they can enter a structure. A mouse can enter a building through an opening as small as a dime (0.5 centimetres) and a rat through a 1.25 centimetres opening that is approximately the size of a nickel. The most important places to rodent-proof are all areas where feed is stored, processed or used, if feasible.

Also, be sure to:

  • Make all necessary repairs around the buildings. Plug holes and burrows.
  • Keep building surroundings clean and free of weeds, bushes and litter heaps or animal carcasses.
  • Install wire netting over
  • ventilation traps and pipes.
  • Store food 30-45 centimetres off the floor and 30-45 centimetres away from the wall for easy inspection and sanitation.
  • Use rodent-proof containers when possible.

Population reduction
To help control the rodent population, using a highly palatable single-feed anticoagulant rodenticide containing active ingredients such as difethialone or bromadiolone is proven to be the most effective way. The key to success is to alternate the chemistry (active ingredient) a few times a year, and use the proper format (paste, pellets, mini-blocks, place packs) in the right locations. Alternating chemistry and format is the best way to prevent bait shyness and to improve bait acceptance during a rodent’s life cycle.

Always ensure that all rodenticides are securely placed in bait stations to prevent children and non-target animals from accessing the rodenticides, which is in line with all CQA programs.

Below are tips for every producer to keep in mind for a successful and cost-effective rodent control program:

  • Use rodenticides with proven effectiveness and high palatability, which will attract rodents. Difethialone is the newest and most active ingredient on the market against rats and mice and because of its high effectiveness, rodenticides formulated with difethialone can be formulated at a lower concentration, which makes the rodenticide virtually undetectable by rodents.
  • Buy a rodenticide product based on the price-per-placement and the price-per-dead-rodent rather than on the price-per-bucket of bait. Purchasing very low-cost rodenticides may require you use more, so the perceived low shelf price may not bring you the cost savings you anticipated.
  • Use enough rodenticides within the bait stations to ensure an uninterrupted supply of bait by visiting and re-supplying bait stations on a weekly basis. Mice gestate for only 21 days, so one needs to visit often to catch the mice before they give birth.
  • Place rodenticides in locations easy for the rodents to reach even if they may be inconvenient for you to attain. Use bait stations every three to four metres inside the barn and every five to six metres outside the barn.

You can also request the services of a biosecurity technician specifically trained in rodent control to come to your farm and educate you and your staff on rodents and how to control them. Biosecurity technicians can even set up a specific rodent control program for your property that is effective and simple to follow. By doing so, every staff member can positively contribute to making your rodent control program a success. A biosecurity technician can also be a great resource to help you tackle the unique problems of your barn as they arise.

By taking the time to develop an effective rodent control program with the aid of an expert biosecurity technician, you will have an effective in-house economical program you can manage, which will certainly contribute to increasing your profitability and reducing the health risks to your herd. With increased public concern over food safety and producers’ commitment to quality assurance programs, there is no doubt that you must have a simple, reasonably priced and effective continuous rodent control program in place.

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