Flock health

Rats and Mice Around the Chicken Coop: Signs, Exclusion, Traps and Bait Safety

Field guide · Updated November 12, 2026 · about 6 min read

Rats and mice come to a coop for spilled feed, water and shelter, and they cost more than feed: one rat eats about 25 pounds a year, and rats break and eat eggs, can kill baby chicks and carry Salmonella and fowl cholera (Oklahoma State Extension). Control starts with locking feed away and closing every gap larger than ¼ inch, then snap traps set where hens cannot reach; poison bait, if used at all, goes only in tamper-resistant bait stations used exactly as the label directs (UC IPM; U.S. EPA). HenClass summarizes that guidance and gives no rodenticide dosing or legal advice.

Rat vs mouse sign chart

The species decides where traps go and how small a gap must be closed. Most sign is left at night, so check with a flashlight after dark (University of Maryland Extension FS-985).

To tell the rats apart, pull the tail forward over the back: a roof rat's reaches at least to its snout, a Norway rat's only to the middle of the skull (UC IPM).

Other signs around the coop

• Gnawed corners and feeders, holes around the coop, a strong ammonia smell, piles of leaves or paper (Maryland; Utah State).
• Burrows, runways, rub marks, unusual excitement in the flock (Oklahoma State; UC IPM).
• Missing feed and eggs. Snakes, skunks and raccoons take eggs too; the predator ID chart sorts those clues.
• Rats in daylight: Oklahoma State reads sign without sightings as about 100 rodents and frequent daytime sightings as thousands.

Why rodents matter

• Eggs and chicks: "Rats have been known to kill baby chicks and break and eat eggs" (Oklahoma State).
• Disease: Oklahoma State names Salmonella and fowl cholera as the main poultry concerns among as many as 35 diseases rodents carry; Maryland says up to 45, including leptospirosis, fowl pox and erysipelas. For people, UC IPM lists leptospirosis, Salmonella and LCM virus, carried by about 5% of U.S. house mice.
• Fire: rats chew wiring insulation (Oklahoma State), one reason the winter care page hangs heat lamps by wire or chain.

Step 1: take away food, water and cover

1. Store feed in metal. Rodents chew wood and plastic more easily than metal (Utah State); Maryland suggests aluminum cans with lids. Never store pesticides next to food (EPA).
2. Bring feeders and waterers in at night. Chickens don't eat or drink after dark; rats do (Utah State).
3. Stop spills. Adjust feeders, clean up spilled feed and use nipple waterers (Maryland), such as the nipple bucket.
4. Remove cover. Mow, haul off lumber and junk (NC State; Oklahoma State) and keep shrubs 2 feet from buildings (UC IPM).

Step 2: rodent-proof the coop and run

Rats chew through plastic, foam, wood and caulk, so steel wool is only a temporary plug; close holes with metal, concrete or galvanized wire cloth (UC IPM). Rats jump 36 inches straight up (NC State), so a raised coop works by removing hiding places, not by being out of reach.

Step 3: traps first, out of the hens' reach

1. Snap traps: "the safest, most effective, and most economical way to trap rats" (UC IPM). Utah State finds wood snap traps with peanut butter work well.
2. Placement: along walls and in dark corners, trigger end nearly touching the wall; for roof rats, also on ledges and beams (UC IPM).
3. Protect the flock: keep traps where pets, children and free-range poultry can't reach (Maryland); use boxes or stations and set traps at night (UC IPM). Oklahoma State suggests windup mouse traps, which won't catch birds.
4. Prebait: leave traps baited but unset until bait is taken, then set them (UC IPM; Oklahoma State). Rats may need at least 5 days to accept a new object (NC State).
5. Enough traps: a heavy infestation may need a dozen or more (UC IPM).

Where sources differ: Maryland and Oklahoma State list glue boards, but UC IPM says they are not generally recommended for nonprofessionals and never for outdoor use. UC IPM also advises against live traps for nonprofessionals, and EPA warns released rodents may return.

Bait stations and rodenticides: EPA rules and the label

HenClass recommends no product or rate; the label governs any use.

• Consumer products must be ready-to-use bait stations with block or paste bait; pellets are not allowed, and second-generation anticoagulants (brodifacoum, bromadiolone, difenacoum, difethialone) are not registered for consumers (EPA).
• Where: consumer labels limit use to indoors or within 50 feet of buildings; tamper-resistant stations are required wherever children under six, pets or nontarget wildlife may reach bait, and for all outdoor above-ground use (EPA).
• Around poultry: use only baits approved for poultry houses (Oklahoma State). Keep bait inside stations, away from pets, children, wildlife and free-range fowl, wear disposable gloves and keep a poison control number handy (Maryland).
• State rules: California prohibits most anticoagulant uses (UC IPM); ask your state agriculture department or extension office.

Secondary poisoning. A rodent killed by a second-generation anticoagulant may hold many times the lethal dose, so pets and wildlife that eat it can be poisoned; EPA says to remove dead rodents promptly. UC IPM warns that "exposure to even a single dead rodent might be enough to poison a pet" and that bromethalin can also pass up the food chain.

Cleaning up droppings and dead rodents

1. Air out enclosed spaces for 30 minutes first (CDC).
2. Wear rubber or plastic gloves. Do not sweep or vacuum droppings or nests; that can put virus-containing droplets in the air.
3. Soak them with an EPA-registered disinfectant or fresh bleach solution, 1.5 cups of bleach per gallon of water, for 5 minutes or as the label says.
4. Wipe up with paper towels; double-bag rodents, nests and used traps for a covered garbage can.
5. Wash gloved hands, remove the gloves, then wash with soap and warm water. More on handwashing: Salmonella and backyard poultry.