Give Rodents the Boot: How to Banish Rats and Mice from Your Barn

by Cynthia McFarland • courtesy of Farnam

If you have horses, you usually have rodents. Whether you see them or not.

“People will tell me, ‘I have barn cats, so I don’t have mice,’ but rodents are nocturnal, so you don’t normally see them,” notes Bill Warner, senior specialty product development manager at Farnam.

“Rats and mice have a faster generation time (birth to maturity) than many insects, so they can have several generations in a year, which can lead to a lot of rodents,” says Warner.

What exactly is a “lot” of rodents? To put it in perspective, mice start reproducing at just four to five weeks of age. A single female can produce up to 56 offspring per year. Norway rats average four to eight offspring per litter and have four to six litters per year.

Both rats and mice reproduce year-round with their reproductive cycle and number of offspring increasing when they have adequate food, water and safe shelter.

All those rodents can cause significant damage. According to the United States Department of Agriculture (USDA), rodents destroy more than $2 billion in feed every year.

Rodents in Residence

So what are the telltale signs that rodents are sharing your barn with your horse?
• Droppings
• Holes chewed in feed bags, plastic containers
• Damage from chewing to blankets, pads, leg wraps, etc. Gnawed wires
• Chew marks on wood (stall ledges, doors, window frames, etc.)
• Smudge marks along walls, pipes, rafters (dark marks left by the oils and dirt in rodents’ coats)

Rats and mice aren’t evil. They’re simply looking for basic creature comforts — food and shelter — and these can usually be found in abundance in a barn.

“Basically, a barn is a giant rodent smorgasbord,” observes Warner. “It’s full of grain products they love to eat and hay/bedding they like to nest in.”

Rats and mice will eat feed and contaminate it with urine and feces even more than they consume it. Chewing on wiring (which they do to wear down their continually growing front teeth) can lead to expensive equipment repairs and may be a fire hazard (damaged wire can cause a short).

In addition, rodent droppings contain bacteria that carry disease, and rodents also hosts fleas, ticks and mites associated with a number of diseases: salmonella, leptospirosis, plague, rickettsialpox, murine typhus, hantavirus, sin agua virus, Lyme disease, tularemia, Rocky Mountain spotted fever, etc. In some cases, a disease can cycle through the rodent population and then affect dogs, horses and humans in the area.

Unfortunately, if you don’t control rodents in the barn, they’re likely to end up invading nearby structures — including your house.

Stop the Invasion

Warner explains that the realistic approach to getting rid of rodents is not complete eradication, but rather — just as with flies — management and control. It’s simply not possible to totally “cure” a rodent situation. You will never eliminate every single rodent, because more will come in from outside your property. However, with the right program in place, you can drastically reduce the population of rats and mice and their exposure to horses and humans.

An effective management program includes:
• Good barnkeeping/cleanliness
• Physical barriers
• Traps
• Bait stations/rodenticides

“If you don’t feed them, they don’t come, so your first goal is to remove what attracts rodents in the first place,” says Warner. “Hay isn’t really the issue; the main attractant is feed, including pellets and supplements.”

This is where good barnkeeping and cleanliness come into play. Since grain and seeds are rodents’ preferred food sources, horse feed in the barn is like putting out a big bowl of candy with a sign that says “Help yourself!”

Even if you use feed within a few days, leaving it stacked in paper or plastic bags will not deter rats and mice, who easily chew through the packaging. Ditto for wooden or plastic containers. To keep grain and feed products safe from hungry rodents, store them in metal bins with tight-fitting lids. Clean metal trash cans are fine for this purpose.

You may be storing feed correctly, but spilled grain in the barn aisle and in stalls is also an invitation to rodents. Remove any uneaten grain from feed tubs and sweep up dropped feed. Dispose of it in a tightly sealed metal trash container instead of tossing it outside the barn or on the manure pile.

Rodents like dark, damp areas, so keep the barn tidy, dry and well-lighted. This includes the tack room, as blankets, leg wraps and saddle pads can be a source of nesting material. Don’t stack fence boards or lumber near the barn and keep the surrounding area mowed so tall grass and weeds can’t offer shelter to rats and mice.

Just closing the door to your feed and tack rooms isn’t enough of a physical barrier to keep rodents out, as they can squeeze through remarkably small openings. Mice can get through holes the size of a dime. (If you have any doubt, there are ample YouTube videos showing just that!) Look for any gaps around windows and door frames, under sinks, around plumbing and electric lines, in hot water heater closets, etc. Pack any small openings with steel wool or stiff metal screen; use caulking to hold the metal in place.

Eliminating feed sources and blocking access will deter a significant number of rodents. Now you can use traps and bait stations/rodenticides to get rid of any remaining rats and mice.

Place “snap” traps along walls with the baited end of the trap facing the wall. “Tunnel” traps work best when placed lengthwise along walls, making it inviting for mice to enter the tunnel. In addition to the predictable cheese for bait, try peanut butter, bacon, butter, chocolate candy or marshmallows. Use gloves when emptying traps and when resetting used traps.

Bait stations/rodenticides can be helpful as ongoing control methods. Rodenticides work by either causing internal bleeding or attacking the nervous system. With both methods, rodents consume the product and later die, typically in their burrows. (Should you find a dead rodent in or near the barn, scoop it up with a shovel or by hand wearing a glove and dispose of it in a sealed trash container.)

“Follow label directions closely for whichever products you use and follow the safety recommendations,” advises Warner.

For best results, place bait stations strategically along walls where rodents are known to travel, as mice have poor eyesight but excellent senses of hearing and smell. Replace bait periodically so the rodenticide remains fresh.

An ongoing management program will go a long way in convincing rodents your barn is not a place to call home.

Rodents Tip #1: Protect Tack and Equipment from Rodents

Your feed room isn’t the only room in the barn you want to safeguard from rodents. The fleecy underside of your good Western saddle and those thick quilted leg wraps make perfect nesting material for mice and rats. Keep the door closed and fill hole and gaps with steel wool or metal hardware “cloth” to deter them from entering. Store out-of-season items like blankets, sheets, leg wraps and bandages in sealed containers (metal is best), making sure they’re clean and totally dry first.

Rodents Tip #2: Don’t Let Rodents Contaminate and Waste Feed

Did you know the average adult rat consumes nearly 10 percent of its body weight in food per day? Rodents contaminate far more feed than they eat from their urine, droppings and hair. To deter rats and mice in your barn, store all grain products, pellets and supplements in metal bins (clean metal trash cans are ideal) with tight-fitting lids. Sweep up spilled feed — including in the stalls — on a daily basis and dispose of it in a tightly sealed metal trash container.