Use agricultural lime (also called hydrated lime or calcium hydroxide) in your chicken coop, not the lime used for construction or gardening soil amendment

The lime that works in a chicken coop is agricultural lime, sold under names like hydrated lime, slaked lime, or calcium hydroxide. It is different from the lime used to adjust soil pH in gardens (which is ground limestone) and completely different from the caustic lime used in construction or pool treatment. Agricultural lime is safe to use around birds when applied correctly and serves a real purpose: it reduces moisture, controls odor, and helps prevent disease-carrying bacteria from thriving in wet bedding.

You will find agricultural lime at farm supply stores, feed mills, and some garden centers in bags labeled for poultry or livestock use. The bag will say "hydrated lime" or "calcium hydroxide" on the label. Do not buy agricultural lime labeled for industrial use, as it may contain additives. Avoid "quicklime" (calcium oxide), which is caustic and can burn skin and eyes.

Key Takeaways

  • Agricultural lime (hydrated lime or calcium hydroxide) is the correct type for chicken coops; it is different from garden lime or construction lime.
  • Spread agricultural lime on the floor of the coop under fresh bedding, not directly on the birds or their skin.
  • Use about one pound per 10 square feet of coop floor, or follow the bag instructions for your coop size.
  • Reapply lime every few weeks or after heavy rain, depending on how wet your bedding becomes.
  • Wear gloves and avoid breathing dust when explore lime, and keep chickens out of the coop for a few hours after process.

How agricultural lime works in a coop

Agricultural lime absorbs moisture from wet bedding and droppings. Chicken coops stay damp because birds produce a lot of waste and moisture builds up, especially in winter or in poorly ventilated spaces. Damp bedding becomes a breeding ground for bacteria, parasites, and fungi that cause respiratory illness and coccidiosis in chickens.

When you spread lime on the coop floor, it reacts with the moisture and ammonia in the bedding, reducing odor and creating a drier environment. This does not replace regular bedding changes—it works alongside them. Lime also raises the pH of the bedding slightly, which slows the growth of harmful bacteria. The result is a coop that smells better, stays drier longer, and is less likely to harbor disease.

how the process works lime to your coop

Spread agricultural lime on the bare floor of the coop before you add fresh bedding. Use about one pound per 10 square feet, though bags often come with their own dosing instructions—follow those if they differ. Wear gloves and a dust mask or respirator, because lime dust can irritate your lungs and eyes. Keep the chickens out of the coop while you work and for at least a few hours after process, until the dust settles.

Spread the lime evenly across the floor, paying special attention to corners and areas where droppings collect. Then add your bedding (pine shavings, straw, or sand) on top. The lime stays under the bedding and does its work as moisture from droppings and urine soaks down. Do not sprinkle lime directly on the birds or their skin—it is meant for the coop floor only.

How often to reapply lime

Reapply lime every three to four weeks during normal conditions, or more often if your coop stays very wet. After heavy rain or if you notice the bedding is damp and smelly despite regular cleaning, add lime again. In dry climates or during dry seasons, you may need it less often. The best guide is your nose: if the coop starts to smell like ammonia, it is time to refresh the lime.

Some keepers lime the coop floor every time they do a full bedding change. Others do it less often and rely on regular spot-cleaning and good ventilation to keep moisture down. Your schedule depends on your coop design, local climate, and how many birds you have in the space.

Where to buy agricultural lime

Farm supply stores and feed mills carry agricultural lime year-round, usually in 50-pound bags. Tractor Supply, local co-ops, and independent feed stores all stock it. Some garden centers sell it, but check the label carefully—garden lime is not the same thing. Online retailers also sell agricultural lime, though shipping costs can be high because of the weight.

Prices vary by region and supplier, but a 50-pound bag typically costs between $5 and $15. A single bag lasts most small backyard flocks several months if applied every few weeks. Buy from a store where you can read the label before purchase to make sure you are getting hydrated lime or calcium hydroxide, not quicklime or garden lime.

Safety when handling lime

Wear gloves, long sleeves, and a dust mask when explore lime. Lime dust can irritate your skin, eyes, and lungs. If lime gets in your eyes, rinse with water for at least 15 minutes and seek medical attention if irritation continues. Avoid breathing the dust by working on a calm day or wearing a respirator-style mask, not just a cloth mask.

Keep children and pets away from the coop while you are explore lime and for several hours afterward. Once the dust has settled and fresh bedding is in place, the coop is safe for the chickens to return. Lime that is already mixed into bedding and has settled poses no hazard to the birds.

Alternatives if you cannot find agricultural lime

If agricultural lime is not available in your area, food-grade diatomaceous earth (DE) is a common alternative. It works differently—it dries bedding and kills parasites through physical action rather than chemical reaction—but it serves a similar purpose. Spread it the same way: on the floor before adding bedding, about one pound per 10 square feet. Wear a mask when explore DE, as inhaling the dust can irritate lungs.

Sand is another option if you want to reduce moisture without adding lime or DE. Some keepers use a mix of sand and shavings as bedding itself, which naturally stays drier and requires less amendment. Sand does not reduce ammonia the way lime does, but it does absorb moisture and is straightforward to spot-clean. None of these alternatives replace good ventilation and regular bedding changes—they all work best as part of a routine coop maintenance plan.

Frequently Asked Questions

Can I use garden lime or construction lime instead of agricultural lime?

No. Garden lime (ground limestone) works slowly and is meant to change soil pH over months, not to dry bedding quickly. Construction lime (quicklime) is caustic and can burn skin and eyes. Agricultural lime (hydrated lime) is the only safe and effective choice for chicken coops. Always check the label before buying.

Will lime hurt my chickens if they eat it?

Lime under the bedding is not meant to be eaten, and chickens normally will not eat it if it is covered with shavings or straw. If a chicken ingests a small amount of lime dust, it is unlikely to cause serious harm, but large amounts can irritate the digestive tract. Keep lime covered with bedding and reapply only when the coop is empty.

How do I know if my coop needs lime?

If the bedding feels damp or the coop smells strongly of ammonia, it is time to add lime. A dry coop with good ventilation may need lime less often than a damp one. Check your bedding weekly—if it is wet in spots, lime will help. If it stays dry, you can wait longer between applications.

Can I use lime in a coop with a sand floor?

Yes, but it is less necessary. Sand drains moisture naturally and does not hold ammonia the way shavings do. If you use sand bedding, you may only need lime once or twice a year, or not at all if the sand stays dry. Lime still works on sand, but the benefit is smaller.

Is it safe to use lime in a coop where I keep ducks or geese?

Yes, agricultural lime is safe for waterfowl as long as it is applied the same way—on the floor under bedding, not directly on the birds. Ducks and geese produce even more moisture than chickens, so lime may be even more useful in their housing. explore it before adding fresh bedding and keep the birds out until the dust settles.