Meat

Meat, in general, is fine for ducks. You can give your ducks cooked beef, chicken, or even duck meat. Fish is also great for ducks, but too much can give your ducks’ eggs a fishy taste. Try to avoid fishes that may be high in mercury. Other seafoods such as shrimp, lobster, and oysters are also fine.

Processed meats should be avoided, however. They are extremely unhealthy for ducks, containing additives, preservatives, and/or too much salt. Don’t feed your ducks bacon, sausage, ham, salami, pepperoni, pastrami, or suchlike. Small amounts won’t kill your ducks, but it’s best to avoid them.

Meat can be fed raw, as ducks are well-equipped to handle raw meat. However, you may cook it if you are concerned about potential pathogens in raw meat.

Eggs

Eggs are high in protein and a complete source of nutrition for ducks. If you have excess eggs, boil them and feed them back to your ducks. Eggs are also a good treat for ducklings. Always boil eggs before feeding them to your ducks. Raw eggs can cause a biotin deficiency and may lead to your ducks learning to eat their own eggs. Chicken eggs, duck eggs, or any other kind of egg are all fine.

Dairy

There’s some debate over whether ducks can or should eat dairy. Ducks are not designed to eat dairy; it’s not a natural food for them. Birds, in general, are lactose intolerant. However, there does seem to be a lot of anecdotal evidence of ducks and chickens doing well when fed a lot of dairy.

Cultured or fermented dairy products contain less lactose and are more digestible. Farmers used to fatten meat birds on buttermilk, and many people give their birds yogurt as a probiotic. Some people think ducks won’t be able to utilize the probiotics in yogurt, but I don’t think that’s true.

Some say that they’ve given their ducks or chickens milk frequently for years with no visible ill effects.

Do ducks know what’s good for them?

You might see your ducks eating tomato leaves. That’s not good for them! Tomato leaves contain solanine, which is toxic.

Or you might see your ducks eating windfall apples—including the seeds, which contain a compound that turns into cyanide once digested!

So how much do they know about what they should and shouldn’t eat?

I believe they have some sense. A few tomato leaves won’t hurt them. I have never heard of a duck gorging on tomato leaves or even eating enough to hurt them. As for apple seeds, they should pass through your ducks’ system whole and entire, and even if they were digested, it would take a lot of apple seeds to harm them.

If given options, ducks will, for the most part, avoid what’s bad for them. There are many, many anecdotes of ducks and chickens being allowed to free-range in an area containing toxic plants and never touching them. Known exceptions include castor beans and foxglove.

On our property, we have a lot of tropical milkweed, which is toxic. We used to pull them up whenever we saw them, but we never got rid of all of them and they kept coming back. I have never seen any of our animals touch them. Also, our chickens have access to our compost pile, which contains avocado seeds and peels, onion peels, and of course rotten and spoiled food. The chickens love the compost pile, but they ignore the avocado and onion. They’ve never gotten sick.

However, if your ducks are in a small run where they’ve devoured all the available greenery and the only sources of green food remaining are tomato plants, rhododendron, and rhubarb, that’s when problems might occur.

If your ducks have a large area, there’s no need to be paranoid or go to great pains to remove everything that might possibly be toxic. They have some sense.

Even so, don’t trust them to always know what’s best.

Chickens have been known to gorge on styrofoam pellets. Ducks are also attracted to shiny things and may gladly gobble up earrings, beads, screws, and suchlike. Maybe they think such objects are beetles or bugs. There are also stories of ducks or other poultry being poisoned from things they ate. I have heard of ducks that died from gorging on avocado.

Be aware of what your ducks have access to, and remove things that could be toxic if you can, particularly if your ducks are in a confined area.

Oxalic Acid

Oxalic acid is an organic compound found in many plants and foods. Because it binds with calcium, consuming too much of it can cause a calcium deficiency. For laying ducks, who need large amounts of calcium to form eggshells, this could potentially be dangerous. The more oxalic acid your ducks consume, the more calcium they will need.

Oxalic acid is found in most plant or plant-based foods. As such, it isn’t something to be avoided, as most foods containing oxalic acid are otherwise very healthy. However, there are some foods that are very high in oxalic acid, and it may be best to avoid feeding them to your ducks or only feed them occasionally. A free-choice calcium supplement may help or even negate the risk, but no one knows for sure.

Here are some of the foods with the highest levels of oxalic acid:

• Almonds
• Amaranth
• Beet greens
• Carrots
• Cashews
• Cassava
• Chives
• Garlic
• Lettuce
• Navy beans
• Okra
• Parsley
• Peanuts
• Potatoes
• Purslane
• Radish
• Rhubarb leaves
• Rutabaga
• Snap beans
• Spinach
• Swiss chard

Various factors affect the oxalate content of each food, but in general, spinach, rhubarb, and tea leaves contain the highest levels of oxalates. Amaranth, cassava, chives, parsley, purslane, and Swiss chard are also extremely high in oxalic acid. These are the foods I would be careful with. Some people will tell you not to feed your ducks spinach at all, but it’s still nutritious and healthy, and ducks love it, so while it should be limited, I don’t think it’s necessary to avoid it entirely.

Almost all plant foods have oxalic acid, so beyond that short list above, I don’t think it’s worrying about oxalic acid in your ducks’ diet, although I could be wrong.

Solanine

The Solanaceae family, also known as nightshades, are a family of plants contanining compounds called alkaloids. One alkaloid, solanine, is toxic and is found in several garden vegetables and plants:

• Potato
• Pepper
• Eggplant
• Tomato
• Tomatillo
• Ground cherry
• Goji berry

In potato plants, the leaves and stems contain the highest concentrations of solanine and should never be fed to ducks. As for the potatoes themselves, any green parts are toxic and should not be fed to your ducks. The peel contains 3 to 10 times more solanine than the flesh, but it would take a very large amount of potato peels to cause issues. The eyes are also higher in solanine and are best removed. The flesh of potatoes contains low amounts of solanine, but likely not enough to present any risk. Boiling causes a slight but insignificant reduction in solanine levels. Since potatoes also contain lectins (although the levels are low compared to legumes), which are destroyed by cooking, potatoes are best cooked before being given to your ducks.

Peppers (including all types of bell peppers and hot peppers) are safe for ducks to eat, containing only low levels of solanine. Pepper plant leaves, stems, and flowers are relatively high in solanine. I was not able to find any credible information on how much they contain. They are not as toxic as potato leaves and stems. My ducks recently decimated the leaves of a potted pepper plant, and there are many other anecdotes of poultry readily eating pepper leaves, so they are likely not very dangerous. Solanine is bitter-tasting because it’s a natural defense mechanism to protect a plant from being eaten, so if the birds are happy to eat them, we can perhaps infer that they don’t taste that bad and hence don’t contain much solanine. I would not recommend giving your ducks access to large amounts of pepper leaves if they don’t have other greens to choose from, but there is no reason to worry if your ducks nibble on occasional pepper leaves.

The same is true of eggplants and tomato plants: the fruit is fine, the rest of the plant is at least mildly toxic. I cannot find any information on how much your ducks would need to ingest to cause an issue. There are many anecdotes of ducks and chickens happily devouring tomato plants without problems, and also anecdotes of ducks and chickens avoiding tomato plants or only barely nibbling them. Unripe tomatoes are also high in solanine and should not be fed to your ducks.

Ground cherries, goji berries, and tamarillos are also nightshades, and the foliage and unripe fruit are toxic. If you have these plants and your ducks can access them, I doubt you need to worry about your ducks poisoning themselves. The aforementioned bad taste of solanine should deter your ducks from consuming a toxic quantity. But if you don’t want to take the risk, you may prefer to remove your ducks’ access to any nightshade plants, especially if your ducks’ run or yard is small and their greenery choices are limited.

Citrus

There are rumors that citrus can cause off-tasting eggs, interfere with calcium absorption, and cause digestive upsets. It’s often stated that poultry should not be given citrus fruits.

It’s a myth that citrus interferes with calcium absorption and causes soft-shelled eggs. On the contrary, studies have found that citrus improves calcium bioavailability and increases calcium absorption.

The other claims may be partly untrue as well. The inclusion of citrus pulp and citrus peels in poultry feed has been studied. At levels of 5-15% of the diet, it appears to be safe, not affecting egg weight, production, or quality. However, it did not seem to have any benefits and reduced feed efficiency at higher rates of inclusion. Dave Holderread briefly mentions that ducks can eat peeled citrus fruits in his book, Storey’s Guide to Raising Ducks.

Nevertheless, ducks don’t usually like citrus fruits. In our orchard, parrots and other wild birds absolutely love obliterating our oranges and grapefruits, but I haven’t seen my ducks or chickens eating fallen citrus. Citrus is very acidic, so there could be some truth to the digestive issues claims, if your ducks eat them in large amounts. If your ducks do like any citrus fruits, they should be fine in small quantities. The peels may also be okay in small amounts.