Can Chickens Eat Onions? What Do the Studies Say?

can chickens eat onions
Chickens can eat onions – in small quantities

If you have been wondering if you can feed your chickens kitchen scraps containing onion and have pondered the question ‘can chickens eat onions?’ Well don’t worry, we have done hours of research to come to a scientific conclusion on whether chickens can eat onions and if it is safe for them to do so.

Yes, chickens can eat onions – but only in very small quantities. 

All types of onions (white, yellow, green, red, spring onions) can be eaten by your chickens in moderation. Like other vegetables onions contain vitamins and minerals and have health benefits for your chickens. 

As long as you only give your chickens onion in very small quantities, you chickens can benefit from eating onions without having any health issues. 

What this article covers

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Nutritional Benefits of Onions

  • High water content (84% water)
  • Contain 1.8 grams of protein
  • Approximately 40 mg of Calcium
  • Approximately 60 mg of Phosphorus
  • Antimicrobial and immune boosting properties

Can Chickens Eat Onions? What Does The Science Say About Chickens Eating Onions?

We spent hours looking through the scientific literature to see what we could find regarding chickens and onion consumption. There have been many studies done on the subject are a few are summarized below:

In 2001, a study was conducted to test if onions had any affect on the flavor of poultry eggs. Researchers fed the chickens onion to see if an onion-like taste would be imparted on the yolk. The study concluded there was indeed a change in the eggs flavor. The more onion quantity a chicken consumed, the more an onion flavor could be detected in the chickens egg. 

A study undertaken in 2004 looked at how onions affected poultry. The researchers fed geese a quantity of green onions. The result was that the geese that consumed the onions were diagnosed with poor liver function and a condition called Heinz anemia (more on this condition further in the article).

A study from 2017 arguably could contradict that consumption of onion by chickens is dangerous. The study was designed by purposely letting chickens forage through onion crops. The chickens had no ill effects from this foraging.

A study from 2020 considered the impact feeding onion extract has on the immune systems of broiler chickens. The results found that the broiler chickens had improved welfare, antioxidant enzymes activity and immune response. The study also concluded that Phenolic-rich onion extracts can be used as a natural growth promoter in the poultry feed for good health and improved performance.

can chickens eat onion
Eating onion can have a positive effect on a chickens immune system

Edible Parts Of An Onion

Predominately the bulb of the onion (the bit that grows underground) is the part of an onion that is eaten by humans  – and this is the case with chickens too.

Chickens should not be fed the tops of green onions, mainly due to having no teeth and the inability to chew. These are difficult for them to break up and consume so these green stalks are generally ignored.

Due to the strong taste and flavor of onions, chickens are not generally attracted to eating them unless very hungry or desperate.

Can Chickens Eat Onion Peels?

Yes. Chickens can eat onion peels – but they would probably be pretty desperate to do so! 

If you offer them onion peels they will most likely take a look and then ignore them. They aren’t the most appealing food on the menu for chickens and they will most likely favor everything else they are given over onion peels!

If they start eating onion peels, then perhaps consider if they are getting enough quantity and quality of food in their diet as onion peels are not something they would typically eat by choice. We use these high quality chicken feed products for our girls.

Is It Dangerous to Feed Chickens Onion?

Yes, there is a key danger to giving your chickens too much onion. This is the reason the suggested daily amount should be less than 0.5% of your chickens body weight.

A condition known as Heinz anemia can affect your chickens if given too much onion. Heinz anemia is a form of hemolytic anemia, which occurs when red blood cells break down faster than the body can replace them. 

This condition has also been associated with dogs and pigs who have eaten too much onion and resulted in ill effect. 

Physical symptoms in chickens from Heinz anemia include listlessness, weakness in the legs and an ill or otherwise unkempt appearance.

This is why it’s super important to give onion to your chickens sparingly. 

The risk of feeding your chickens too much onion is a condition called ‘Heinz anemia’

How to Prepare Onions for Your Chickens

If you have some onion in your kitchen scraps you would like to give to your chickens, the best way to prepare the onion is to cut it into very small pieces. 

This way you can easily measure how much onion you are giving to them (keeping in mind the less than 0.5% body weight rule) and also the onion will be in an easier format for the chicken to swallow and digest. You can buy great vegetable choppers such as this one that chop up the onions into tiny pieces and with ease. This allows you to easily quantify the amounts being given.

Your chickens will most likely eat the onion raw in this form but to go a step further you could cook the onion to make it even more appealing to their senses as it will reduce the strong smell and favor that onions generally have. 

Chopping onion into small pieces helps regulate feeding amounts

So, in conclusion now your question of ‘can chickens eat onions?’ has hopefully been answered. Onions won’t hurt your flock as long as they are only given as described further up in the article. Go ahead and confidently give your chickens kitchen scraps containing onion but remember – only very sparingly!

Chicken Care Shopping List

Are you looking for a shopping list of everything you need when caring for your precious flock? We have put together an easy reference of items for your convenience. 

Wanting to learn some incredible chicken facts that will blow your mind? Read on here!

References

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AUTHOR

The team at My Chicken Guide are chicken enthusiasts! Our team has over 20 years experience in raising and caring for chickens. Our head writer is a qualified Environmental Scientist with a passion for sharing accurate and scientifically based knowledge on chicken care.