What to Do With Rained-On Hay: Salvage, Feed Value, and Selling It

By the XES Netting team — bale net-wrap manufacturer · Updated August 16, 2026 · ~15 min read

1. Identify the rain event and define the lot

Start a written record before moving the forage. A useful lot is forage from the same field, cutting, crop and maturity, rain history, harvest operations, intended package, and storage conditions. Split the lot when any of those conditions changes. Record measured rainfall from the best available local gauge or weather station, not an impression such as light or heavy rain.

The event stage changes the question:

Event	What to record and decide
Rain before cutting	This is not rain on cut hay. Record field access, soil condition, crop stage, disease or lodging, and any delay in maturity before deciding when to cut.
Rain immediately after cutting	Record crop moisture at the event, amount, intensity and duration. Freshly cut forage may respond differently from wilted forage, but timing alone does not clear it for baling or feeding.
Rain after partial drying	Record drying time before rain, swath or windrow form, handling already completed, and leaf condition. Rewetting and another handling cycle can change soluble nutrients, leaf retention, ash, drying uniformity, and microbial exposure.
Rain on a nearly dry windrow	Treat the lot as rewet and potentially uneven. A crisp surface does not describe moisture inside the windrow or future package.
Repeated events	Keep each event and each handling pass in the record. Do not convert several events into one average rain amount or one assumed quality-loss percentage.
Floodwater, standing water, runoff, soil or manure contact	Stop the ordinary rain-damage workflow. Identify possible biological, chemical and foreign-material contamination before considering feed, baleage, mulch, field return or disposal.
Rain on already-baled or stored hay	That is a storage and post-baling problem, not this page's main scope. If heating is possible, use the emergency temperature gate below.

2. What rain studies can and cannot tell you

Rain can extend plant respiration, leach soluble compounds, increase microbial activity, bleach color, and increase physical leaf loss. The size and direction of a measured change depend on location and climate, crop, maturity, rain amount, intensity and timing, drying duration, handling, package, and the outcome measured: dry matter, leaves, crude protein, soluble carbohydrate, fiber, digestibility, mold, or another endpoint.

The University of Arizona Cooperative Extension summary of rain impacts on alfalfa hay illustrates why one percentage is not defensible:

Evidence reported by the source	Measured outcome	Boundary for this decision
Utah artificial-rain study summarized in an Arizona alfalfa publication; 0.8 inch of rain	Estimated losses reported separately for yield (9.7%), available carbohydrate (18.8%), crude protein (10.2%), lipids (19.8%), and soluble minerals (14.0%)	The Extension summary does not provide every maturity, climate, handling, drying, or package detail. These values describe that cited alfalfa experiment, not a universal rain-loss formula.
Michigan field-cured alfalfa study summarized by the same source; 0.7 inch at constant intensity spread over 1 to 7 hours	Dry-matter loss ranged from 4% to 13%, with the highest loss under the longer-duration event	This measured dry matter under one rain amount and duration design. It does not establish feed suitability, a price discount, or the result for another crop, maturity, climate, handling system, or rain pattern.

Those results differ by measured endpoint and experimental boundary. They should be shown separately, not averaged into a claim that a given inch of rain causes a fixed nutrient, tonnage, or dollar loss. A current representative analysis of the actual lot is more useful than transferring a study percentage to it.

3. Drying and handling after rain

Re-conditioning, tedding, raking, or inverting may improve exposure, but no operation is automatically correct after rain. Use it only when the crop, maturity, leaf moisture, soil bearing condition, terrain, weather, equipment manual, and local Extension guidance support that operation. Set equipment to avoid scraping soil or manure into the forage. Additional handling can increase ash and can remove leaves, especially from legumes that have become dry and brittle.

Inspect several locations across the field, including heavy windrows, low areas, shaded edges, and changes in crop density. Record each handling pass. Sunshine and elapsed time can support drying, but neither proves package moisture, restores leached nutrients, removes contaminants, or makes moldy forage safe. Feel, a twist test, color, smell, and animal interest are screens only; none releases the lot.

4. The direct moisture gate for dry hay

Do not bale the full lot until the intended package passes a representative direct moisture check. Package matters because a large, dense bale dissipates heat and moisture differently from a small bale.

Purdue Extension's no-effective-preservative targets are 20% moisture for small rectangular bales, 18% for large round bales, and 17% for large rectangular bales. Treat those as named source- and package-specific targets, not universal clearance. Crop, density, local climate, equipment, preservative label, buyer specification, insurer, and local Extension guidance may require a lower limit.

Use a method that fits the decision:

• Define the lot and package. Do not mix fields, cuttings, rain histories, crops, packages, or storage conditions in one release result.
• Use the exact meter manual. Confirm that the instrument covers the expected moisture range and package, then follow its sampling locations, compression or probe procedure, temperature correction, calibration check, and maintenance instructions.
• Measure a range, not one favorable spot. Sample representative windrow locations and trial packages across the lot. Record the meter model, method, calibration check, locations, bale/package type, individual readings, minimum, maximum, and time.
• Use direct drying when the decision matters. Virginia Cooperative Extension states that controlled oven drying is required for accurate forage moisture concentration and describes rapid farm estimates. Confirm a consequential or borderline decision with the receiving laboratory's direct method rather than assuming a field meter is exact.

A baler monitor, a windrow reading, one probe reading, feel, or a favorable average does not clear wet pockets. If the package-specific target fails, stop dry-hay baling. Do not assume additional sunshine or a preservative will correct an unmeasured package.

5. The separate post-baling heating and fire gate

This gate applies after forage has been packaged. It does not authorize baling above a dry-hay moisture target. NDSU Extension says hay fires usually occur within six weeks of baling, so at-risk hay needs monitoring through that period rather than for only the first few days.

Internal hay temperature	Purdue/NRAES action
125°F or lower	No action at this reading. Continue the monitoring plan when the hay is in an at-risk lot.
150°F	Entering the danger zone. Check twice daily. Separate stacked hay only if it is safely possible and consistent with local fire-service direction.
160°F	Reaching the danger zone. Check every couple of hours. Separate only if it is safely possible and consistent with local fire-service direction.
175°F	Hot spots or fire pockets are likely. Stop air movement if possible and alert the fire service.
190°F	Fire is likely. Remove hot hay only with fire-service assistance; exposure to fresh air can produce flames.
200°F or higher	Fire is imminent. Remove hot hay only with fire-service assistance; exposure to fresh air can produce flames.

The ladder above follows Purdue's reproduction of NRAES-18 critical temperatures and actions, with movement conditioned on safe local fire direction. NDSU sets a stronger stop boundary: above 175°F, or if there is smoke or a burning odor, call the fire department immediately and do not move hay or expose it to oxygen. Do not walk on a stack that may contain a fire pocket.

6. Contamination and feed-safety stops

Ordinary rain and floodwater are not the same event. Nebraska Extension states that hay, silage, or grain contacted by floodwater that may have encountered chemicals from buildings or cities should not be fed and must be disposed of under applicable rules. Standing water, runoff, soil, manure, petroleum, pesticide, sewage, dead animals, foreign material, or unknown upstream sources require a contamination decision before any feed or baleage plan.

Also stop and identify:

• the field's pesticide products, rates, dates, grazing or harvest intervals, crop restrictions, and residue or manure-use restrictions on the current label;
• toxic plants, weeds, foreign material, nitrate-risk history, and crop stress;
• visible mold, dust, heating, discoloration, reduced intake, or unusual odor; and
• the intended animal species, pregnancy status, age, growth, lactation, respiratory sensitivity, health history, and complete ration.

NC State Extension documents that some herbicide residues can remain active in hay and manure and that label restrictions and written communication must follow the material. A rain event does not cancel the label. A laboratory analysis also does not replace a legal label restriction.

There is no blanket feed clearance. Mold and dust can reduce intake and cause respiratory or digestive problems; toxin effects can be reproductive, neurologic, hepatic, renal, or otherwise species-, toxin-, and dose-specific. University of Georgia Extension notes that horses are particularly susceptible to moldy forage and respiratory disease, while ruminant tolerance does not make every mold or dose acceptable. Smell, color, animal interest, an apparently clean interior, soaking, steaming, dilution, feeding a different species or class, or using the lot first does not clear it. University of Minnesota Extension's steaming study found that steaming reduced viable mold and dust in tested hays but did not remove mold from the forage and should not replace low-mold, low-dust hay.

7. Baleage is not a generic rescue

Baleage is a complete ensiling system, not wet hay covered at the end of a failed drying attempt. Virginia Cooperative Extension places low-moisture silage or haylage at 40% to 60% moisture. Within that broader range, Purdue Extension identifies 50% to 60% moisture as its best range for proper baleage fermentation. That difference should not be averaged: use the current source, crop, package system, local climate, operator experience, wrapper and film instructions, and receiving ration requirements that govern the actual operation.

A suitable system requires all of the following:

• an appropriate crop and maturity with enough fermentable carbohydrate, not overmature or unsuitable material;
• measured package moisture in the selected authoritative range;
• low soil and ash contamination and no flood, manure, pesticide-restricted, toxic-plant, moldy, spoiled, or otherwise contaminated forage;
• a dense, uniform bale made for the wrapper system;
• immediate complete oxygen-barrier sealing after baling; Purdue says ideally within four hours;
• the current film and wrapper manufacturer's specified film type, layers, overlap, tension, width, and maintenance; Purdue's system uses six to eight layers of 1-mil sunlight-resistant plastic;
• puncture-free handling, frequent inspection, prompt repair with the film supplier's compatible ultraviolet-resistant tape, suitable storage, completed fermentation, and controlled feed-out; and
• laboratory and veterinarian or nutritionist review when fermentation or animal suitability is uncertain.

Net wrap can bind a bale before film is applied, but net wrap alone is not an oxygen barrier. It does not create baleage. Net wrap is also not a moisture barrier: it does not make a bale breathe, continue drying safely, become waterproof, prevent mold, or make rained-on hay safe. If the crop, system, operator expertise, sealing capacity, storage, monitoring, or feed-out plan is unavailable, stop and get local Extension and veterinary guidance rather than treating baleage as a rescue.

8. Representative analysis and professional interpretation

First define the field/cutting/storage lot. Then ask the receiving laboratory for its current package- and question-specific sampling and submission protocol. Penn State Extension defines logical lots by field and cutting, recommends coring toward the center from the curved side of large round bales and through the end of square bales, and gives minimums of 10 large bales or 20 small bales before combining cores. Follow the receiving laboratory's current protocol when it differs.

Prefer an NFTA-certified laboratory or another laboratory that documents equivalent methods, proficiency testing, and quality control. The National Forage Testing Association certifies participating laboratories against recognized reference methods and publishes its certified-laboratory list; that program does not imply that every receiving laboratory is NFTA-certified.

A basic nutrition panel commonly includes dry matter, crude protein, NDF, ADF, an appropriate energy estimate, ash, and minerals. Add tests only when the lot history and receiving professional indicate them, including mold or mycotoxins, nitrate, toxic-plant compounds, pesticide or environmental contaminants, soil/manure/flood indicators, and heat-damaged protein reported as HDP, ADIN, or ADICP. Nebraska Extension explains why ordinary crude protein can overstate available protein after heating and recommends HDP or ADICP when caramelization is suspected.

Record the sample date, lot, protocol, bales and locations sampled, laboratory, methods, report date, and whether values are as-fed or dry-matter basis. A negative result is evidence about the submitted composite, not proof that clustered mold, a toxic plant, a chemical pocket, soil/manure, or flood debris is absent everywhere. Have a veterinarian or qualified nutritionist interpret the report for the intended species, pregnancy, age, growth, lactation, respiratory sensitivity, health history, intake, and complete ration.

9. Use this decision flow

1. Identify the event, lot and history. Record crop, maturity, field/cutting, rain dates, measured amount and source, timing, duration, operations, pesticide and contamination history, intended package, and intended animal.
2. Apply the moisture and fire gates. Do not make full-lot dry hay until representative package moisture meets the controlling target. If hay is already baled and heating, use the fire ladder and local fire service.
3. Apply contamination stops. Flood, standing water, runoff, soil, manure, toxic plants, pesticide restrictions, foreign material, mold, dust, or unknown history can stop feed and baleage routes.
4. Obtain representative analysis. Follow the receiving laboratory's package- and question-specific protocol, prefer an NFTA-certified laboratory or another laboratory documenting equivalent methods, proficiency testing, and quality control, and add history-triggered tests.
5. Compare the evidence with the animal and ration. A veterinarian or nutritionist interprets the lot for the actual animals and ration; the article does not certify feed suitability.
6. Choose a supported outcome. Professionally condition and use the lot only when evidence supports it; redirect it to a legally and safely supported non-feed use; or reject and dispose of it under local environmental, pesticide, weed, fire, and waste rules.

Do not use a static hay price, per-ton loss, rain discount, treatment return, or seasonal market rule. If an economic decision is necessary, use the current local lot analysis, measured recoverable dry matter and quality, handling and testing cost, legal restrictions, delivery terms, and the buyer's written terms. Safety and label restrictions are not negotiable price adjustments.

10. What a seller should disclose

Provide a written lot record; do not promise that the hay is suitable for a species, class, or ration. Include:

• lot identifier; field; cutting; crop and variety when known; maturity or stage; harvest dates;
• rain dates; measured source, amount, timing, intensity or duration when available; standing-water, runoff or flood history;
• conditioning, tedding, raking, inverting and other operations after rain, with dates;
• baling date; package type; moisture instrument and method; calibration check; sample locations; individual range; any preservative product, rate and label record;
• round-bale WIDTH × DIAMETER, rectangular dimensions, density when known, and weight with its moisture basis;
• maximum recorded temperature, measurement method and location, and the six-week monitoring record for an at-risk lot;
• storage dates and conditions, base, cover, ventilation and weather exposure;
• observed mold, dust, odor, pests, weeds, toxic plants, foreign material, soil, manure, floodwater, runoff and chemical history;
• the current representative laboratory report, report date, as-fed or dry-matter basis, laboratory, sampling protocol, bales sampled and requested analytes; and
• price, quantity, delivery terms, known restrictions, and a clear statement that no feed-suitability guarantee is made.

Frequently asked questions

The bottom line

Rain creates a new decision record, not an automatic salvage route or automatic loss. Separate the event stage, measure the intended package, stop for fire or contamination hazards, sample the defined lot, and let qualified professionals connect the evidence to the animal and ration. A supported feed use, a legally supported non-feed use, or rejection and disposal are all possible outcomes; none can be guaranteed by rain amount, appearance, net wrap, or this article.

Evidence reviewed: University of Arizona Cooperative Extension, Purdue Extension, Virginia Cooperative Extension, NDSU Extension, Nebraska Extension, Penn State Extension, NC State Extension, University of Georgia Extension, University of Minnesota Extension, and the National Forage Testing Association. Each source is linked next to the claim it supports. Accessed August 16, 2026.

Featured photo: Hay windrows on the mowed field by Santeri Viinamäki, own work, licensed under CC BY-SA 4.0, via Wikimedia Commons. The image was visually verified on August 16, 2026; it shows cut forage in windrows in a dry-hay field, not film-wrapped baleage.