Will old bird seed hurt birds?

Bird lovers often wonder if feeding birds old or expired bird seed could potentially cause harm. This is an important question, as we want to make sure we are providing safe and nutritious food for our feathered friends. In this article, we’ll explore whether old bird seed can hurt birds, signs of spoiled bird seed, how to properly store bird seed to maximize freshness, and when it’s best to throw away old bird seed.

Can old or expired bird seed hurt birds?

In most cases, feeding birds older bird seed is unlikely to cause harm. Bird seed can maintain its nutritional value for quite a while after the “best by” date printed on the packaging. However, at some point, bird seed will degrade in quality and can start growing mold, bacteria, and fungi. Consuming moldy or rotten bird seed could potentially make birds sick.

Some signs that bird seed has spoiled and may be unsafe include:

  • Visible mold growth
  • Foul, musty odor
  • Discoloration
  • Sliminess
  • Presence of bugs or larvae

Bird seed that displays these characteristics should not be fed to birds and should be discarded. It is not worth taking the risk of birds consuming unhealthy food.

How long does bird seed last?

How long bird seed stays fresh and safe to eat depends on several factors:

  • Seed type – Mixtures with oil seeds or fruits like peanuts, sunflower seeds, raisins and other dried fruit tend to have shorter shelf lives. Plain millet and milo last longer.
  • Storage conditions – Bird seed stored in a cool, dry spot away from sunlight will stay fresher longer than seed kept in a hot garage or shed.
  • Packaging – Unopened bags maintain freshness longer than opened bags. Well-sealed containers are ideal.
  • Turnover – The faster you go through bird seed, the less chance it has to stale or spoil. Buying seed in smaller quantities can help.

Properly stored, unopened bags of bird seed typically stay fresh for 9-12 months past the packing date before starting to lose flavor and nutrition. Once opened, most bird seed will last 4-6 months with proper storage. Monitor your seed for signs of spoilage and stick to this timeframe for the best quality.

How to store bird seed properly

To get the most life out of your bird seed purchase, follow these tips for proper storage:

  • Keep bird seed in a cool, dry spot. The ideal temperature is between 50-70°F.
  • Store in sealed containers like a bin or bucket with a tight lid. This prevents moisture from getting in.
  • Avoid exposure to sunlight, which can accelerate spoilage.
  • Store bird seed off the ground on shelves or pallets to minimize dampness.
  • Buy bird seed in small quantities that can be used up quickly.
  • Use oldest seed first and add fresh seed on top to rotate supply.
  • Check regularly for signs of spoilage like mold, bugs, foul odor, etc.
  • Discard any seed that looks or smells bad – don’t take chances with old seed.

Following these guidelines will help your bird seed stay as fresh as possible to provide your backyard birds with the healthiest food.

Signs it’s time to throw out old bird seed

Here are some clear indicators that bird seed has gone bad and needs to be discarded:

  • Visible mold – Mold spores on bird seed can be harmful to bird health. Discard moldy seed immediately.
  • Foul, musty smell – Fresh bird seed smells like grain. Foul odors mean it’s rotten.
  • Weevils or bugs – Weevils and larvae indicate bugs have invaded the seed which can spread to other feeders.
  • Slimy texture – Bird seed should not be wet or slimy. This signals spoilage.
  • Discoloration – Changes from original color can mean deterioration.
  • Rancid smell – If oil seeds like peanuts or sunflower seeds smell rancid, they’ve gone bad.

Trust your senses – if something seems “off” about your bird seed, it’s better to be safe than sorry and toss it out. You can replenish your supply with fresh bird seed.

Can spoiled bird seed make birds sick?

Eating moldy, insect-infested, or rotten bird seed carries some risks for birds, including:

  • Digestive issues – Spoiled seed can irritate the stomach and intestines, causing discomfort, diarrhea, vomiting.
  • Illness – Harmful bacteria like salmonella or fungi can cause sickness if ingested.
  • Toxicity – Mold produces mycotoxins which can be toxic to some animals and potentially birds.
  • Poor nutrition – Outdated seed loses its vitamin and mineral content over time.
  • Dehydration – Food poisoning can cause fluid loss, dehydration, and weakness.

Consuming a small amount of spoiled bird seed likely won’t cause major harm. But ingesting a large quantity, mold, or bacteria can make birds unwell. Rotten seed lacks proper nutrition as well. It’s best to play it safe and only offer birds fresh, high-quality seed.

Can spoiled bird seed harm chickens or other animals?

Like with birds, feeding chickens and other animals spoiled bird seed could potentially cause some adverse effects including:

  • Digestive upset, diarrhea
  • Dehydration
  • Illness from mold, bacteria
  • Poor nutrition from degraded seed

Chickens and birds have sensitive digestive systems, so it’s best not to take risks by feeding old seed. Ruminant animals like cows and goats are even more sensitive. Make sure to also keep spoiled bird seed away from outdoor pets, rodents, and wildlife who may eat it.

Discard old seed instead of dumping it outside or composting it, which can spread mold and bacteria. Follow guidelines on seed bags for proper disposal.

How can you safely feed birds old seed?

Bird experts don’t recommend deliberately feeding birds seed that is past its prime. However, here are some tips to reduce risks if you have no choice but to use older seed:

  • Inspect each scoop or handful, removing any clumps, spoiled seeds, hulls, or foreign objects.
  • Discard any seed that appears moldy, discolored, foul-smelling, slimy, or contaminated with bugs.
  • Mix old seed 50/50 with fresh bird seed to dilute any degraded seed.
  • Feed smaller amounts of older seed so it’s consumed quickly.
  • Ensure birds have access to fresh water to stay hydrated.
  • Monitor birds closely for any signs of illness after eating older seed.

Again, it’s wisest not use seed that is months past its expiry date or displaying signs of aging. Rely on visual and scent clues to determine if seed is still wholesome enough for birds to consume.

How to tell if bird seed is rancid?

Rancid bird seed has a very distinct, unpleasant odor you’ll notice immediately. The smell is caused by the oils in seeds like sunflower, peanuts, and corn going bad. Here are a few ways to identify rancid bird seed:

  • Strong paint-like, bitter smell
  • Greasy, yellow appearance
  • Taste is terrible, biting
  • Makes you cough if smell inhaled

Rancid seeds are dry and crumbly with little oil remaining. The high oil content of these seeds makes them spoil faster than plain millet, milo, and wheat. Toss out any rancid seed and clean feeders well with bleach before refilling.

Should you feed birds moldy bird seed?

It’s not recommended to deliberately feed birds moldy bird seed. Some risks associated with birds consuming moldy seed include:

  • Digestive issues like diarrhea
  • Potential mycotoxin poisoning
  • Respiratory issues if mold is inhaled
  • Bacterial or fungal infections

While small amounts of mold may not make birds seriously ill, the effects can be unpredictable. Certain types of mold like Aspergillus flavus produce toxic substances that can be harmful when ingested. It’s better to be safe than sorry and avoid feeding moldy seed to birds.

Check bags for mold growth before purchasing. At home, inspect seed frequently and discard any portions that grow mold. With proper seed storage and rotation, you can minimize chances of mold.

Can expired bird seed kill birds?

It’s unlikely that feeding birds expired seed alone would directly kill them, but it does pose some health risks, especially if the seed is growing mold. Here are a few possibilities:

  • Toxic mold can cause organ damage and eventual death but this is rare.
  • Salmonella or other bacteria could kill younger, weaker birds.
  • Lack of proper nutrition can leave birds weakened.
  • Bird parents feeding chicks old seed can indirectly harm them.

While death is an extreme and uncommon result, it’s best not to take chances. Monitor seed freshness closely and discard any that is past its prime. Maintaining clean feeders and offering nutritious feeds is the healthiest approach for backyard birds.

How do you get rid of old bird seed?

To properly dispose of old, expired bird seed, follow these recommendations:

  • Discard in household trash in sealed bags – not compost.
  • Avoid dumping outdoors where wildlife could access it.
  • Mix with water and seal in bags to prevent germination if disposing outside.
  • Burn spoiled seed carefully by mixing small amounts with newspaper. Avoid inhaling smoke.
  • Donate unopened bags within recommended use date to wildlife rehab centers if they will accept it.
  • Follow disposal guidelines on packaging to ensure proper destruction of any insecticides or chemicals.

Be sure to also thoroughly clean any feeders that contained spoiled seed using a diluted bleach solution. Rake up and remove any discarded seed from the ground below feeders as well.

Can you compost old bird seed?

Bird experts generally advise against composting most old bird seed, for a few reasons:

  • It can spread mold, fungi, and bacteria into your compost.
  • Decaying bird seed can attract unwanted rodents and critters.
  • Compost won’t get hot enough to kill harmful pathogens.
  • Seeds may sprout and overtake compost.

Plain seed hulls may be ok to add in moderation. But don’t compost mixtures with fruits, nuts or oily seeds. Stick to household green waste in compost instead. Discard spoiled bird seed in sealed plastic bags in your normal garbage.


Feeding birds old, expired seed now and then likely poses minimal risk. But bird seed that is growing mold, has a foul odor, is discolored or slimy should always be discarded. The small effort to maintain and replace bird food is worth it to protect our feathered friends.

With proper storage in a cool, dry place, most bird seed will stay fresh for many months past its packaging date. Monitoring for moisture and signs of spoilage allows you to spot old seed in time. By taking a few simple precautions with purchasing, storing and handling bird seed, we can keep backyard birds happy, healthy and returning to feeders for years to come.

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