Rodents are the most common pests in barns and stables. They consume and waste feed, ruin tack and other equipment, and in some instances spread disease. So it’s wise to try to keep them out of the barn and get rid of any that venture in. But pest management can be challenging and frustrating, and usually takes a combination of tactics.
Cleanliness is Job #1
Diligent cleanliness is the first line of defense. That means reducing the amount of food and nesting material available to these freeloaders. If the barn is clean, they won’t be so apt to move into the building in droves and multiply.
All animals have three requirements for life: food, water and shelter. If you can remove any one of these three essentials, you will force unwanted intruders to leave or at least make it harder for them to stay. Even though there may be places inside the barn where they can hide and take cover, if you keep everything clean and picked up, there will be fewer places to hide.
If the area around the barn is clean, they won’t have much cover when trying to get to the barn—and will be easier prey for cats, hawks, owls and other predators. Keep weeds and tall grass mowed down around the outside of the buildings so rodents won’t have places to hide as they come in. Eliminate piles of debris, and don’t leave unused equipment parked next to the barn. Grass and weeds that grow up around these would provide a lot of cover for rodents. Use concrete, sheet metal or other foolproof materials to exclude rodents from places where they might crawl into buildings.
Mice are the most ever-present pests, and they are generally easier to control than rats. Dr. Thomas Barnes, wildlife extension specialist at the University of Kentucky, said rats can be extremely difficult to control. “They are very smart and hard to catch. Dealing with rats without rodenticides (poisons) is difficult.
“The first line of defense in controlling mice or rats is to look at places they might find food or nesting sites,” he said. Reducing these attractants can be challenging, however, in a setting where you have grain, straw, and other essentials of rodent life. Do whatever possible to reduce the amount of spilled or wasted feed, and clean up potential nesting areas.
“Good maintenance is important, with no piles of material for them to hide or nest in,” he said.
“If you have cats and dogs, don’t leave their food out,” said Barnes. "Pick it up and put it away. Self-feeders for horses are not a good idea; rodents will eat from those. Take a close look at the tack room and feed room, and plug any holes and cracks. You can use insulating foam that will fill an odd-shaped hole."
Steel wool poked into a hole can also create an effective block.
If you are trying to trap rodents, set traps in the most advantageous locations. “Look for the oily spots where they’re going in and out of a hole or rubbing against wood," said Barnes. "Place sticky glue traps along their travel areas. Today many people use glue traps instead of snap traps. The glue traps are easier to work with, though you have to deal with the animal once it’s been caught. Check all traps frequently.”
Barnes added, "If you can identify travel lanes and patterns where rodents are coming and going, this will help in trap placement. You don’t have to buy expensive commercial traps. You can buy the sticky chemical (polybutene) to spread on cardboard and make your own sticky traps.
“If you have cats, dogs or horses that might step on the sticky traps, put the traps inside a PVC pipe of proper diameter for the rodents to go through,” advised Barnes.
Rodents like to travel through this type of small area because they feel safe.
You don’t have to bait the sticky traps, he said. And keep in mind that if there’s an abundance of food in the barn, they might not be interested in bait.
“If you do use bait, the best kind is a mixture of peanut butter and oatmeal," said Barnes. "This works very well because rodents are attracted by the odor of peanut butter. The mix is easier to deal with than some other types of bait. You can make a bait ball and put it in the middle of a piece of PVC pipe, then place your glue traps on either side of it. If you put this in their travel path where they are going back and forth, it can work very well.”
When using traps, make sure you have plenty. “If you see one mouse, you’ve probably got dozens," said Barnes. "People often feel that if they’ve caught one mouse, they’ve solved the problem. Make sure you have sufficient traps out there, and be persistent.”
Some types of traps have the ability to capture several rats or mice with one setting or baiting. Uncooked oatmeal sprinkled inside the trap with a trail of meal leading out is often successful. The disadvantage of this type of live trap is that the rodents inside it must then be killed.
“Not very many people want to live trap rodents, but if they do, there’s a type of trap called the Sherman Live Trap," said Barnes. "These can be baited with peanut butter and oatmeal, and you can adjust the treadle sensitivity. For small rodents you can set it so it’s very sensitive. If you look at the trap and it’s closed, you know there’s a rodent inside.”
Know the keys to using snap traps successfully. “Most people just put one trap against the wall where they know the rodents travel, and put it parallel to the wall. This doesn’t work nearly as well as placing it perpendicular to the wall," said Barnes. "You also need to put two together, side-by-side. If you put it parallel, you only have one shot at that critter. If you miss him, you won’t have a chance to catch him again.”
If you have two traps there, however, and he triggers one and jumps over it, he might land on the next one.
Mice tend to have a very small home range; they usually stay within 10 to 30 feet of their nest. Set traps or bait stations six to 10 feet apart. If food is abundant and mice won’t take the bait, you can often trap them by using nesting material as a lure, such as a small cotton ball tied to the trigger of a snap trap.
Rats have a larger home range. It is best to set rat traps along their runways or favorite travel routes. One way to identify their runways is to sprinkle a fine layer of flour or baby powder in the areas you suspect are being used, and then check for tracks.
Remember that rodents always possess the potential to spread disease. Wear rubber gloves when handling dead rodents or traps, and always wash your hands thoroughly after handling traps.
“Some methods don’t work for controlling rodents," noted Barnes. "You hear about ultrasonic devices, but those don’t work at all. There are no repellents that work. Cats and dogs catch the occasional rodent, but not enough to make a real difference.”
You will never completely eliminate a rodent population, but you can reduce them if you are diligent. They’ll keep coming in, so you have to be prepared to keep up control strategies.
“You’re trying to keep the population to a manageable level,” he said.
“Most people don’t want to use rodenticides, but if you have a really bad infestation, trapping may not be enough [see sidebar below]," said Barnes. "You may have to hire someone to use rodenticides to clean out the rodents. They reproduce prolifically, and you may have to get the population down to where you can then keep it to a manageable level with other methods.”
The University of Kentucky has a publication containing tips for rodent control, setting traps, etc., at www.ca.uky.edu/forestryextension.
SIDEBAR: CHEMICAL CONTROL
Editor's Note: Many horse farm owners and managers do not want to use chemical controls against rodents. However, sometimes the problem of rodents goes beyond normal trapping control measures. Extreme caution is needed when using chemical controls, and you should consult an expert to ensure you are getting chemical control that won't harm your other animals.
The most common rodenticides are anticoagulants formulated as baits. When the rodents eat the baits, the chemical acts to thin their blood and they die from internal bleeding. These rodenticides are safe to use in barns and stables as long as you follow label directions and only put them in enclosed bait stations where children, horses, cats and dogs won’t have access to them.
Use rodent poison on or near their regular runways or entry holes; check bait every few days so you can replace any that has been eaten or discard any that has become wet or dirty. Limit their access to other food or water, or put bait in places where they'll be attracted or feel comfortable using it—in hidden corners or their familiar haunts.
Grain-based baits in meal or pellet form can be placed along runways. Rodent blocks with wax base (which rats and mice are attracted to for gnawing) can be nailed to vertical surfaces along rafters or other off-the-ground rodent runs. Some poisons are available in water-soluble concentrates to make a liquid bait; this type is attractive to rodents that have plenty of food available but no water source. Another form are tracking powders, which are applied in thin layers (using a squeeze bulb) along a runway or in a bait box. The powder sticks to the fur or feet of rodents as they travel over it. They eat the poison as they groom themselves, or carry it with them back to their nests where it may kill other rodents as well.
Collect and burn any dead rodents you find. Some poisons may be harmful to your cat or dog if it eats some of the dead rodents. Always read labels when using rodent poisons and follow directions, especially the safety precautions.