Can Ducks Eat Onions? (Answered)

by Alex Kountry
Updated on

Onions are useful bulb-like plants which we use in seasoning our dishes and a lot of people love and enjoy them.

However, it is not such a great commodity to be offered to ducks. You should avoid feeding onions to ducks as it is toxic and poisonous to them.  

Onions contain thiosulphate, which can hinder red blood cells and cause hemolytic anemia in birds, as well as cause abnormally sized red blood cells to occur in large amounts.

As much as onions are beneficial to humans, it should be avoided if possible with ducks and the possible reasons would be highlighted in this article. 

What Are The Health Benefits Of Onions For Ducks?

Can Ducks Eat Onions

Onions are impressive plants which have a lot of health benefits embedded in them.

As we all know, the use of onions in human cooking is very healthy, however to ducks it is not very safe for consumption.

I will explain some of the nutritional value of the onion plant:

1. Antioxidants 

Onions are antioxidant rich. Antioxidants help the body reduce inflammation, and cholesterol levels and this in turn helps to decrease the risk of heart disease. 

Their powerful anti-inflammatory properties may also aid in the reduction of hypertension and the prevention of blood clots.

2. Calcium 

Onions have a good serving of calcium and have been discovered to help bone formation and density. 

Onions have been found to help decrease cell damage, increase antioxidant levels, and minimize bone loss, which may help to prevent osteoporosis and increase bone mass

3. Potassium

Onions are a good source of potassium. Most adult humans lack potassium and do not take enough foods to get it in their system. 

Potassium is required for proper cell function, fluid balance, muscle movements, kidney function, and neurotransmission.

4. Antibacterial properties

Onions are packed with antibacterial properties which help to fight off and inhibit the growth of bacteria in the body.

Dangerous bacteria such as E.coli, Bacilli and Staphylococcus have all been inhibited in the body by the presence of onions. 

5. Fibers 

Onions are rich in fiber which is good for digestive health. Onions also contain prebiotics which help the growth of gut bacteria that produce fatty acids.

These gut bacteria which are good bacteria break down the prebiotics to get to work. 

6. Vitamins

Onions are vitamin packed vegetables. It is high in Vitamin C which helps in tissue repair, immune health, and iron absorption.

Onions are also high in B vitamins, such as Folate and Pyridoxine, both of which are essential for metabolism, red blood cell production, and nerve function.

Here is a comprehensive list of foods I wrote on what ducks can eat

How Often Should I Feed Them Onions?

Most people would advise not to feed ducks onions because of the potentially toxic effects it has on them.

Onion poisoning occurs a lot and this can be worse when onions are fed in excess to the ducks.

Onions are not regular food for ducks and if you have to feed them at all, it should be in minimal quantities in well cooked foods. 

Onions contain thiosulphate which causes ducks to have digestive problems as they cannot digest thiosulphate properly.

You would also have to watch leftovers you feed to the ducks if they have onions in them.

If you cook treats for the ducks with onions and still feed them leftovers made with onions, you run the risk of them having onion poisoning.

Can Baby Ducks Eat Onions?

Ducklings should not be fed onions in any form whether cooked, raw or powder as this can not only cause digestive problems but eventual death for them.

Ducklings should be placed on a strict duck starter feed.

Most treats given to ducklings should only start when they are about 4 weeks of age and they have developed enough that their bodies can take care of themselves.

The commercial starter feed sold for ducklings has the nutrients especially protein which they require to mature.

Feeding ducklings onions would only predispose them to anemia and eventual death.

If possible avoid giving them leftovers till they are about 4 weeks and regularly double check to ensure the food doesn’t contain onions. 

Can Ducks Eat Onion Skins?

Ducks might not even eat onion skins because to be honest it is not exactly a great taste that they would love to eat. 

Because of the presence of thiosulfate in onions, it is non-persona grata for ducks and on the list of foods to avoid for them.

Repeatedly feeding ducks onions in any form whether raw, green, skins, bulbs, powder or cooked will make the thiosulphate compound build up.

This then leads to ruptured red blood cells eventually causing the decrease of the red blood cells, and in turn leads to anemia and death.

Can Ducks Eat Green Onions?

Green onions are toxic to ducks and other poultry birds.

In ducks, they have been shown to cause stomach upset, weakness, tachycardia, lethargy, collapse, and even death. 

If for any reason you have to feed onions to your ducks avoid feeding them green onions.

Despite their milder flavor as they could be scallions or spring onions, it is best to not feed them to the ducks.

Although the ducks might look fine when you feed them green onions once, if you continue the behavior, they might end up getting onion poisoning.

If you regularly feed your ducks leftover food then it is best you watch what you give to them or alter the amount of onion you put into your food.

This is because green onions are used a lot in human cooking and you should in fact watch them so they don’t get onions in excess.

Also check out this article I wrote on can ducks eat rice

Things To Consider When Feeding Ducks Onions

Feeding onions to ducks is not advisable for duck owners. We have explained the reasons why feeding the ducks onions is potentially harmful and dangerous to them.

Feeding onion to them in any form does not reduce the dangers that come along with it.

Even when onions are cooked, the thiosulfate compound is still very much present and since the ducks cannot process it, it remains in their body and causes problems. 

When you continue to feed them onions repeatedly, the thiosulfate builds up and you run the risk of ruptured blood vessels and eventual death to your flock. 

What Are The Ways Of Feeding Onions To Ducks

If for any reason you would want to feed onions to your ducks, then it should be in cooked food in minimal quantities.

Cooking onions does not reduce the amount of thiosulfate in it.

Most people avoid feeding their ducks onions deliberately but the vegetable is still found in most foods cooked by humans.

Takeout, pasta and a whole lot of food are prepared with onions in mind.

As such, be mindful of how you feed your birds leftovers to avoid health problems for them. 


As a duck owner it is important that you know what it is that you should feed to ducks and the foods you should avoid. 

Onions, as much as they are beneficial to humans, are very toxic to ducks because they possess a compound called thiosulfate which the ducks body system cannot process to digest.

As such it is usually advisable for duck owners to avoid feeding onions to their flock.

Repeatedly feeding onions to ducks leads to a buildup of thiosulfate which causes ruptured blood cells, anemia and eventual death.

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About the author

Alex Kountry

Alex Kountry is the founder of HayFarmGuy and has been a backyard farmer for over 10 years. Since then he has decided to write helpful articles that will help you become a better backyard farmer and know what to do. He also loves to play tennis and read books


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