When it comes to raising livestock, there are no animals that even come close to the wide-ranging diet of pigs. Pigs are true omnivores and will eat all kinds of plant matter, meat, eggs, and a lot more. And of course, pigs have the reputation of eating absolutely anything, including people food and some downright inedible things like pieces of a wood fence!

As it turns out, pigs aren’t invincible, and if you give or let your pigs eat the wrong things, it could make them deathly ill or even kill them.

I know you don’t want that to happen, and to help you prevent that tragic outcome, I’m bringing you a list of things that are downright toxic for your pigs to have. We’ll get right into the list below.

Moldy Grains or Other Food

Far and away, one of the single biggest foodborne risks to your pigs is that of mold, and particularly moldy grains.

That’s because molds that often contaminate food that is too old or has gotten wet will produce mycotoxins, devastating and often deadly poisons which can kill your pigs before you know what’s happening.

These mycotoxins vary in effect depending on the exact species of mold that produces them. Some cause kidney issues, others cause severe liver damage. Some result in necrosis of skin and muscle, or even organ tissues. Immune system suppression is a devastating secondary effect that will complicate treatment. It all just depends, but none of it’s good.

You’ll have to worry about mold and the risk of mycotoxins anytime grains like corn get wet or your herd’s food is kept in a warm, wet bin or trough. Moisture plus time is the enemy here.

Don’t treat your pigs like garbage disposals and give them old, spoiled, rancid, or moldy food. Any trace of mold in food supplies is a sign that it should be disposed of. Even a little can have life-altering consequences for your poor pig!

Salt

Pigs love salt, and more importantly, they need it in their diet just like all mammals. However, too much salt is bad for them and can cause chronic health problems, and very high amounts can cause immediate sickness and even death.

Excess salt in the blood, a condition known as hypernatremia or sodium poisoning, is exacerbated by dehydration.

Giving your pigs lots of salty food, too much wet ration which tends to be high in salt, or letting them lap up runoff from a mineral or salt block that’s gotten wet can easily result in sodium poisoning.

Be on the lookout for potential causes of sodium poisoning, and if your pig seems to be uncoordinated, is bumping into or pressing its head into things, or just seems disoriented, it’s possible that they are suffering.

You want to get them rehydrated, but do so very slowly and gradually: giving them too much water too quickly could result in fatal brain swelling!

Algae

Algae are another surprising and potentially deadly plant for your pigs, specifically the blue-green varieties which often grow in still or stagnant water during the warm seasons. These are toxic, dangerously so, and very fast-acting.

Symptoms include frothing at the mouth, respiratory collapse, vomiting, excess mucus production, and bloody diarrhea. Death, when it occurs, is usually very sudden and precipitated by total collapse and coma.

Obviously, you should keep the water source that your pigs drink from clean and clear of all contaminants, including algae. Never let your pigs drink from or be forced to drink from stagnant puddles, ponds, runoff, or old livestock tanks or pools.

Paint and Wood Stain

Pigs like to chew on all kinds of things, including your fences and any nearby buildings. Paint and wood stain often have ingredients that are toxic if ingested, especially things like coal tar.

Do whatever you have to do to stop your pigs from ingesting painted or stained materials, and consider investing in livestock-safe surface coatings for future construction.

Green Tomatoes

Green tomatoes are not something that pigs should eat, as they contain dangerous amounts of solanine, a glycoalkaloid neurotoxin.

Ripe tomatoes, though, are safe for them in moderation (though they can cause diarrhea if they have too many).

Green Potatoes

Potatoes, surprisingly, are related to tomatoes as nightshade plants and accordingly, green potatoes also contain very high amounts of solanine.

The skins and sprouts are especially toxic. Avoid them, and it’s a good idea to peel ripe potatoes and discard the skins before giving them to pigs!

Nightshade Greens

All plants in the nightshade family, including veggies like tomatoes and potatoes mentioned above along with peppers and eggplant, contain solanine at all stages of growth and maturity and should never be fed to pigs.

Pigs won’t necessarily avoid these items if they encounter them on your property, so ensure they cannot get to them.

Raw Beans

Raw beans are very bad news for pigs, and also for people!

That’s because they contain phytohemagglutinins and other lectins which can cause significant stomach and intestinal damage, and a host of other problems like severe diarrhea, slowed growth and healing, liver damage, and more.

Different types of raw beans contain different amounts of these toxins, with red kidney beans being the very, very worst.

Note that you can feed pigs cooked beans which have been properly prepared by soaking and then boiling them. However, many types of beans, and especially canned beans, contain high amounts of sodium which can result in sodium poisoning as detailed above.

Stone Fruit Leaves and Pits

The leaves and pits of stone fruit – ones like peaches, plums, and cherries – are toxic and should not be fed to pigs. They can safely eat the flesh of the fruit and the skins, but you’ll want to avoid giving them whole fruit or pits and leaves that you’ve plucked off of your own fruit.

Oak Leaves and Acorns

Pigs eat all kinds of plants, and that includes leaves and nuts, but you shouldn’t let them have oak leaves and acorns. Young tender leaves and green acorns are highly appealing but also highly toxic.

Ingesting a few might cause digestive upset and diarrhea. But eating freely from acorns for several days will usually result in bloody diarrhea and kidney damage.

It’s okay if your pigs eat a handful now and then, but if they are allowed to graze regularly from oak trees on your property, it is only a matter of time until serious symptoms start to show up.

Dark Chocolate

Chocolate is typically a bad idea for pigs generally because it contains theobromine and caffeine. Many common varieties, especially milk chocolate, don’t contain much and might not cause any problems for your animals, but dark chocolate is a whole different story.

The darker the chocolate, or cocoa, the more theobromine it generally contains, and giving dark chocolate to your pigs or large quantities of other chocolate can quickly result in theobromine poisoning.

It’s best not to risk it, even if feeding pigs confectionery waste is an accepted practice in some areas.

A small amount every once in a while might not cause any real or lasting harm, but it’s better to be safe than sorry.

Parsley

Parsley is a remarkably healthy veggie for people, and not just a garnish, but it is shockingly toxic to pigs because it contains compounds which cause photosensitization, meaning sensitivity to light.

This, in turn, will lead to severe blistering on the mouth and lips, and potentially elsewhere on a pig’s body.

These effects are especially horrible for light-skinned pigs. Make sure to remove any parsley growing on your property from areas where pigs can reach it, and avoid feeding it to them.

Parsnips

Parsnips contain the same photosensitizing compounds that parsley does, and should never be given to pigs.

Alcohol

Every now and then, I come across videos on the internet of people giving beer to a pig and laughing their asses off as it stumbles around drunkenly. It infuriates me every time I see it.

It’s not funny, it’s not a prank, it’s not something that should ever be done for any reason, least of all getting some useless clicks on social media. You should never give your pigs alcohol, of any kind, for any reason.

Alcohol is highly toxic to pigs, and causes their stomach to distend dangerously even if they don’t get that much. High doses or chronic ingestion will result in liver damage quickly.

Yes, pigs are sometimes given so-called brewer’s waste, the leftover grains used to make beer and liquor, and most of the time this is fine because the fermentation process is halted.

However, every once in a while, brewer’s waste will keep fermenting after ingestion, meaning it is creating alcohol in the pig’s stomach and digestive tract!

This, naturally, can result in sudden, perplexing, and acute alcohol poisoning. Though rare, it has happened and continues to happen. Think twice before you give your herd any leftover grains used for brewing.