PHOTO: Ana Hotaling
Ana Hotaling
September 26, 2018

Autumnal weather recently brought some much-needed relief to sweltering Michigan, and I for one was thrilled. Stepping outside at 7:30 a.m. to be blasted with sultry, tropical air is not something I enjoy… unless of course I’m by a beach somewhere. My flocks vastly prefer the cooler clime, too. Instead of hiding in the shade or within their coops, they happily ranged again. Yet as my birds explored the withering grasses in the cooler air, something unpleasant nearby hunkered down in preparation for winter. I saw the telltale signs as I opened coop storage areas: Mice were in our henhouses.

Having lived in the country for years, it wasn’t a big surprise. While it’s dismaying to find these little visitors, it’s simply a fact of life. Rural areas have field (deer) mice as well as house mice, while suburban and urban areas have the latter. It doesn’t matter how clean we keep our homes or our henhouses. Mice seeking a safe, warm shelter—especially one with food and water—will find a way in, especially as fall arrives.


Mice Have Many Ways In

Mice are mini-athletes that perform amazing physical feats to access their chosen havens. They can climb, tunnel, jump and swim their way into chicken coops. They use their teeth to gnaw through wood. They squeeze in through the tiniest cracks and gaps: A mouse can fit through a hole 1/4-inch in diameter (about the size of a pencil eraser). Mice also enter through the same pop door that your birds use. Chicken-wire and 2-by-4 fence wire—the most commonly used fencing for chicken runs—let mice stroll right on in.

Look for the Signs of Mice

What told me that mice were in our coops? The presence of scat. Tiny dark droppings dotted the white lids of our feed-storage buckets in the Ameraucana coop and the New Orpington coop. Fortunately, these buckets are made of sturdy plastic with tight-fitting lids; had we stored our chicken feed in their original sacks, they would have had holes nibbled in them and crumbles spilling onto the ground.

I quickly emptied the storage compartment of each coop, looking for matted grass, feathers and weeds pulled together to form a mouse nest. Finding nothing, I checked the sideboards for gnaw marks, another sign of mice. I also checked for rodent tunnels delving into the ground from the coop floor. Finally, I watched the chickens’ behavior. If there were a serious rodent infestation, the birds would be agitated, disturbed and jittery. Luckily, they behaved like their normal selves.

Mice Make Themselves at Home

Once mice have entered a coop, they easily burrow under the litter and into dirt floors—and of course, these two coops are our only ones with natural dirt floors. That’s not to say that mice ignore coops with constructed floors. Concrete and sturdy wood might thwart mice from tunneling through the floor, but any space between the ground and the constructed floor presents a perfect spot for mice to spend the winter: shelter, protection and warmth, with nearby access to food.

Conduct a Thorough Investigation

When droppings appeared to be the only sign of mice in our coops, I shooed a couple of loitering hens outside so I could conduct a more thorough investigation. First, I emptied the nestboxes of shavings and nestpads. The last thing I wanted was a mouse digging a tunnel to its own egg restaurant. Next, I removed the feeders and watering fonts, then I lifted the stands we use to elevate them off the floor. In past winters, I’ve discovered cozy mouse nests beneath the waterers, with field mice dozing snugly under the warm protection of the base heater. Finally, with a hard rake, I carefully sifted through the bedding, searching under the shavings for nests or for the mice themselves.

Discourage Mice From Taking Up Residence

Keeping our coops free of mice and other rodents is simply an impossible task. Even if we built our birds bunkers surrounded by cement walls, mice would still find a way to get in. The best we can do is to limit our open invitation to them as best as we can. Here are some steps you can take to do the same:

  1. Seal all holes, gnawed or otherwise, with rodent-proof materials. Hardware mesh serves well, but get 1/8-inch hardware mesh as mice will fit through the holes of 1/4-inch mesh. If you caulk, use a silicone sealant instead of a gnawable latex one. Avoid sealing holes with materials such as rubber, plastic sheathing and green cement, as mice can chew through these.
  2. Clean up spilled feed. Yes, chickens are messy and scatter their feed everywhere. Trying to end that is a losing battle. If a human-caused spill occurs, however, don’t leave the jumble of crumbles for the chickens to eventually clean up. Doing so is the same as stating, “Dinner is served!” to the local mice.
  3. Remove all feeders at night. Mice are mostly nocturnal and avail themselves to your birds’ feeders while the chickens roost and snooze. Store your feeders in a spot rodents cannot access.
  4. Collect eggs regularly. Eggs are an excellent source of food for mice, and eggs left in nestboxes overnight can attract unwanted guests to your henhouse.
  5. Keep the area 3 to 5 feet around your coop mowed and free from clutter. Tall grass, weeds, trash, stacks of wood, abandoned yard tools and other junk make perfect temporary (or permanent) shelters for mice. A neatly mowed yard also allows you to easily check for rodent burrows and pathways.
  6. Set mousetraps up in areas where you see mice droppings. Position the openings of your traps toward the walls, as mice tend to run along the walls rather than through an open space. To prevent accidents with inquisitive chickens, set your traps at night and remove them during the day. Avoid using pellet bait that contains rodenticides, as these can be ingested by your birds. Also avoid using glue boards and strips; while these might be nontoxic, they leave a live, suffering mouse with sharp incisors for you to deal with.

Disinfect to Protect

Mice have been linked to such poultry diseases as mycoplasmosis, coryza, salmonellosis and hemorrhagic enteritis. To keep your birds—and yourself—healthy, wear protective gloves when dealing with a rodent problem, and thoroughly disinfect anything that might have been contaminated by mice, their urine and their droppings.

I spent several hours replacing bedding, cleaning feeders and waterers, and scrubbing our feed storage buckets. I was watched, of course, by very curious chickens. Tonight, I’ll set traps in our coop storage areas with the hope of ending our status as a mouse vacation spot—at least for now.

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