Are Thistle Seeds Safe for Chickens? What You Should Know

Chickens, Feeders & Food /

Last updated on August 14th, 2022 at 09:51 am

Thistle seeds that are widely fed to garden or backyard birds are actually nyjer, at times spelled as niger, nyger, or nijer. These small, slender, and black thistle seeds aren’t of the problematic weeds of the genera Carduus, Cirsium, but that might not mean they are safe for chickens.

Thistle seeds are safe for chickens if they are from the nyjer or niger plant, i.e., Guizotia abyssinica. Weed thistle seeds aren’t safe for chickens or for your backyard or garden. In contrast, milk thistle seeds and their aqueous solution are safe and healthy for chickens.

Why Thistle Seeds Are Safe for Chickens

For clarity, every mention of thistle seeds in this post refers to nyjer or niger. The sole exception is milk thistle, whether it’s a seed or an aqueous solution.

Whenever I discuss weed thistle seeds, I shall mention it accordingly.

Thistle seeds are not only safe for chickens but also a favorite of many species, especially the winter birds that may flock to your backyard or garden.

Some of these birds are:

  • Finches
  • Doves
  • Sparrows
  • Siskins
  • Juncos
  • Redpolls
  • Buntings
  • Towhees

However, weed thistle seeds aren’t a practical option.

There are many species of weed thistle in the wild, so it is neither possible nor scientifically accurate to definitively state whether all their seeds are safe or unsafe for chickens. 

Also, chickens may not eat weed thistle seeds.

The only reality I can vouch for is the danger weed thistle seeds pose to your property. All weed thistles belong to the Asteraceae family.

Most of these weeds are perennial and invasive, be it Cirsium arvense or Canadian thistle or the Onopordum acanthium, or Scotch thistle.

Perennial weeds like thistles are likely to have roots lingering in the ground even after you win a war to remove everything you can see.

So, steer clear of these weeds and go for nyjer or niger thistle seeds. 

The bags you get on Amazon.com or at your local stores have sterile seeds, as they are treated to heat or irradiated.

There’s no risk of those seeds germinating in your yard.

Nyjer Seeds Are Nutritious for Chickens

Nyjer is a registered trademark.

The Wild Bird Feeding Institute owns the trademark, but all its members and even non-members can use the name as long as they follow the guidelines.

This may be a reason why some companies use different spellings for these thistle seeds.

Irrespective of spellings, Guizotia abyssinica or nyjer seeds are rich in the following nutrients:

  • Protein
  • Fiber
  • Fat

Hence, these thistle seeds are not only safe but also nutritious for chickens. 

Consider the example of egg-laying chickens. These chickens need a steady dose of many nutrients, including the following:

  • Protein
  • Calcium
  • Sodium
  • Phosphorus

Nyjer seeds contain all these four nutrients and more. In fact, these oilseeds have 661 to 867 milligrams of phosphorus per 100,000 milligrams of weight.

Here’s a complete list of minerals present in niger/nyjer thistle seeds, in order of abundance:

  • Phosphorus
  • Potassium
  • Magnesium
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Copper
  • Manganese

The nutritional value and availability of these thistle seeds are the primary reasons for their relatively higher costs.

For instance, sunflower seeds cost much less than nyjer, but they aren’t as nutritious. 

Plus, many grain-eating birds crave the protein and fat content of these oilseeds, particularly in winter.

This fundamental health benefit can boost the growth and general wellbeing of your chickens.

If you’re looking for premium quality thistle seeds, check out Wagner’s Nyjer Seed Wild Bird Food from Amazon.com.

This 5-pound bag may be sufficient for chickens, but you need a larger stock if you also wish to feed other garden or backyard birds, especially goldfinches, doves, and juncos.

Should you decide to feed thistle seeds to chickens, keep the nyjer bags in a dry and cool place, away from moisture and heat sources.

You should use an airtight container or store the seeds in your freezer if you aren’t sure of the frequency of use.

Furthermore, don’t overload your bird feeders with these thistle seeds. The nutritious oilseeds don’t endure moisture as well as sunflower seeds.

Nyjer or niger seeds can turn stale or grow mold sooner than others, and your birds or chickens may not eat them. 

Besides, you should not feed moldy or infested seeds to any birds, and wasting a more expensive seed variety is certainly undesirable.

Milk Thistle Seeds Are Safe and Healthy for Chickens

The only variety of weed thistle that is safe for chickens is Silybum marianum, otherwise known as milk thistle.

While this species is a weed, it isn’t perennial, and there are proven health benefits for chickens.

One study assessed the effects of milk thistle seeds in the starter and grower diets of broiler chickens. Here are the key findings: 

  • Milk thistle seeds boost the growth and weight gain of broiler chickens.
  • The seeds have no adverse effect on fattening or muscularity grade.
  • The milk thistle seeds enhanced the meat value of the chickens.

Therefore, the study concluded that farmers can use milk thistle seeds accounting for up to 2% and 3% of the total starter feed and grower diet, respectively, for broiler chickens.

They further state that milk thistle seeds are beneficial for chickens throughout the entire growing period.

Another study assessed the effects of milk thistle in an aqueous solution. 

Milk thistle extracts are available as concentrates or tinctures, too.

This study concluded the following after testing more than 100 broiler chicks in three treatment groups:

  • Milk thistle extract in an aqueous solution has a significant impact on growth performance.
  • The aqueous solutions of milk thistle increased the antioxidant capacity in the chicks’ blood serum.
  • Feeding milk thistle to the birds boosted the development of their pectoral muscles and welfare.

An aqueous solution isn’t necessary and probably unfeasible if you only want to feed some solid food to your chickens.

So, you may check out Starwest Botanicals’ Organic Milk Thistle Seed or Frontier Co-Op’s Organic Whole Milk Thistle Seed. 

Both are 1-pound bags, available on Amazon.com. But they are substantially more expensive than nyjer or niger thistle seeds.

Wagner’s or other brands and their 5 to 50-pound bags are a much more viable alternative for chickens.

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