By Cheryl K. Smith, Oregon – Shortly after I moved to my homesteading land 15 years ago, I found a desiccated weasel in the barn. It was a long-tailed weasel (Mustela frenata), about 10 inches long from nose to tail tip, and brown in color — which indicated that it had died between spring and fall (they turn white in the winter). New to the country, I thought it looked cute and was sorry I didn’t see a live one. Little did I know weasels killing chickens is all too common.

My next encounter with a weasel occurred 10 years later and didn’t involve actually seeing one — dead or alive, but waking up to find half my chickens dead. Yup, a case of a weasel killing chickens from my coop. They had been dragged to all corners of the chicken coop — not eaten, but nearly decapitated. (Naturally, hens and not roosters.) Unable to determine where a critter could have gotten in and repair or block it, I experienced the same horror the next morning. I knew I had to do something — making weasel traps was possibly the answer.

I had designed the coop myself, believing that it was invulnerable to opossums and raccoons killing chickens as well as more obvious chicken predators. (That cute little dried-up weasel was but a distant memory.) I noticed only in hindsight that the multitude of rats that were digging under the chicken house had gradually disappeared.

The word “weasel” conjures up visions of a sneaky, devious person, or a vicious little mammal that attacks poultry just for the thrill of the kill. Think of the thieving gang of weasels portrayed in the children’s book Wind in the Willows.

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Weasel words are those that are twisted or misleading, used to benefit the individual uttering them. This is believed to have come from the idea that weasels suck eggs; so weasel words are those in which the meaning is sucked out. But in fact, weasels do not have the necessary jaw muscles to suck eggs (or blood from a chicken’s neck).

When I started researching these animals, my frame of reference grew out of all of these misconceptions. I believed that my chickens had their necks chewed through because the weasel was just interested in sucking blood. My explanation for the multiple dead bodies in the corners of the chicken coop was that the weasel was on a killing spree.

These ideas are all wrong, though. As it turns out, weasels are usually more beneficial than harmful. In fact, I probably have weasels on the property right now and am not even aware of them.

Weasels in North America

The Mustelidae (weasel family) is quite large, consisting of not only weasels but minks, ferrets, martens, badgers, and otters. The subgroup Mustela (true weasels) consists of up to 16 species. The long-tailed weasel (Mustela frenata) is the most widely distributed weasel and is found in most of the United States. Other common weasels in this area are the least weasel and the short-tailed weasel or ermine.

Long-tailed weasels range from 11 to 16 inches in size, including the tail, with the males larger than the females. They are normally light brown, with a white belly and black-tipped tail. Some varieties molt their brown coat and become white in the winter. They are long-necked and short-legged creatures, a helpful adaption for getting into small places. Their voice is said to be a high-pitched shriek.

Reproduction and Lifestyle

Long-tailed weasels have only one litter each spring, regardless of food supply — unlike least and short-tailed weasels, which can have a second litter in late summer. The actual gestation period is from 205 to 337 days; however, the mating occurs in the spring and then the ball of cells called a blastocyst floats feely in the uterus for nine to 10 months before implanting and developing into a kit.

Three to 10 babies are in each litter; the babies are called kits. Once kits are born and the mother starts lactating, she does not go into heat for another 65 to 104 days. She can also protect herself and her kits from interested males by choosing or making a den with entrances too small for them to enter.

Kits are born with fine white hair covering their bodies. They get their razor-sharp milk teeth in three or four weeks but do not open their eyes for another week or so. They can start eating meat after about a month — in their blind condition — but may not be weaned until they are up to three months old. They finally reach full size at six months of age but are sexually mature several months before then.

Weasels are mostly nocturnal and solitary, living in dens that are constructed under rocks or logs in a hole, usually near a water source. The den is dry and padded with leaves and even fur from some of their prey. Weasels are also known to move into the previously used den of another ground dweller such as a prairie dog, rabbit or gopher.

Their range is normally 30–40 acres. They spend most of their time on the ground, but also sometimes climb trees.

Males live separate from the females and kits. This leaves the burden of feeding the kits entirely to the female. According to biologists, males will occasionally bring a dead mammal to the female’s den, but such generosity is linked to their desire for sexual activity rather than feeding the young.

Weasels on the Farm

Weasels are actually more beneficial than detrimental on the farm — most of the time. They eat rodents, fish, birds, and frogs, as well as eggs. They are excellent helpers around the chicken house, as long as the rodent population is thriving because they normally prey on a species that is regularly available. Only when they are running out of food — especially when they have young to feed — do they turn to chickens as a food source.

Because weasels eat other small animals such as mice, shrews, voles and rabbits, they can also help protect the vegetable garden. The lanky-bodied weasel even has the ability to pursue these critters down into their burrows.

Weasels also provide food for foxes, coyotes, hawks and owls. So their presence may help the chickens in another way — redirecting the predators to another food source.

Understanding Why Weasels Killing Chickens Happens in Sprees

When prey is in short supply, weasels will often kill more than they and their kits can immediately eat. The females with kits need to ensure that they will survive, so they take what they can get. This is how the idea that they are thrill-killers arose.

Their killing instinct is also triggered by movement — which is why “freezing” by small rodents may protect them. In a chicken coop, the weasel is unable to stop itself from killing.

First, the wild, squawking and flapping movement of the chickens triggers the instinct, causing the weasel killing chickens to go on killing until it perceives there is nothing left to kill. Second, it will want to kill as many prey as possible, with plans to save the extras for future meals. This is why my chickens were dragged down behind the feed cans into corners. The weasel was trying to hide them, most likely with plans to return later.

The method that weasels use to kill their prey is to bite the back of the neck of the animal. The long teeth penetrate the neck with only two bites. This signature method of killing led to the myth of blood-sucking.

Preventing Weasels in the Chicken Coop

Despite their helpful attributes, it is wise to try to prevent weasels from ever getting inside a chicken coop. The best time to do this is when you are constructing it. Do not build the coop directly on the ground; put a floor in it or make sure it is raised up in some way. This was my mistake. I paid attention to trying to prevent holes in the top and sides, while the rats were digging holes underneath. When that food ran out, a weasel used those very holes as a way to get in and get chickens.

Another essential to keeping weasels out of the chicken coop and other buildings is to make sure that there are no openings larger than one inch — or even less if you want to be extra sure. (The common saying is that weasels can get in through a hole the size of a quarter, which is 7/8-inch across.) The best method is to use 1/2-inch hardware cloth or a similar material in areas where you want ventilation. Make sure the coop is completely enclosed.

As time goes by, rodents will start to gnaw holes in the wood. Be aware of these and repair them quickly. Pieces of metal, even flattened tin cans work well to cover such hole.

If a weasel has already caused chicken losses, consider a live trap. Havahart has an extra small live trap that will work for weasels, for only about $24. Make sure it is set so as not to harm other animals. Although the damage is done by the time you determine a weasel is killing chickens, you can still try to trap it to prevent future losses. You will need to live somewhere that you can release it far from its range so as not to create a nuisance for others.

Because weasels are fur-bearing animals, check with your state Fish and Wildlife Department regulations before trapping with a trap that kills weasels.

Like in most affairs, the best advice is to be proactive. Make sure your coop is secure and be aware of the rise and fall of various wildlife populations, such as rabbits and rats.

What are strategies for preventing a weasel killing chickens on your farm or in your backyard?

Names for a group of weasels: Boogle, Gang, Pack, Confusion

Cheryl K. Smith raises chickens and Oberian dairy goats in the coast range of Oregon. She is a freelance writer and the author of Goat Health Care and Raising Goats for Dummies.

Originally published in the September/October 2014 issue of Countryside & Small Stock Journal and regularly vetted for accuracy.