Is Lawn Fertilizer Safe For Chickens? Should It Be Organic?

Taking care of chickens is hard work and keeping track of everything when you first start raising chickens can feel overwhelming. Many folks like to see their chickens run loose on their lawns but then they start worrying, will the fertilizer I use on my lawn have any impact on my chicken’s health?

Is lawn fertilizer safe for chickens? Yes, only if it is organic fertilizer, synthetic fertilizer contains chemicals that are harmful to chickens and could have an impact on any eggs laid during this time and should not be eaten.

It is worth noting, however, that the best lawn fertilizer of all can be chicken droppings which definitely won’t hurt your chickens or their eggs.

Lawn Fertilizers And The Effects On Chickens

It’s probably a bad idea to use a synthetic fertilizer anywhere that chickens graze. While it is unlikely that they will consume enough fertilizer to suffer harmful effects – why risk it? We’ve not been able to track down any cases of fertilizer poisoning in chickens but it’s possible, we suppose.

The best options are SROF (Slow Release Organic Fertilizers) which contain nothing but natural ingredients and which are completely non-toxic to your flock. Some of these contain the droppings of other poultry but are completely pasteurized – so there’s no risk of picking up any diseases from it. One product I like to use is MicroLife 6-2-4 or 8-4-6.

Watch Out For The Eggs

There is a real risk to chickens using synthetic fertilizers, we’d be much more cautious of eating any eggs that were produced from birds that had consumed these fertilizers – it’s likely that any fertilizer present in the blood would find its way into the eggs and over time anyone eating these eggs might get enough toxic build up to cause harm.

Please note that this is pure speculation but it is based on typical redistribution of other toxins when chickens consume them. Again, there are no cases on record of fertilizer poisoning in humans from consuming eggs but again, why risk it?

Are Chickens Good For The Lawn?

Chickens can have both positive and negative effects on your lawn and it’s important to understand this before deciding how to provide access to your lawn for your chickens.

Will Chickens Kill Grass?

This question isn’t that easy to answer as it depends on the size of the area of grass/garden your chickens have access to.

Chickens will naturally scratch and dig to pick through the ground to forage for insects, weeds, seeds, worms, etc. on your lawn. If they are left in the same area which isn’t particularly large then they will soon create a brown patch in your garden.

This can be managed by providing access to specific areas, simply fix chicken wire to wooden posts to section of areas.

By managing your chickens you can use their natural instinct to your advantage as they will eat unwanted insect pests and also turn and fertilize your soil with their poop. These activities are all good for your garden and can help ensure you need to mow less often and use less weed killer and/or pesticide.

The Best Fertilizer Is Chicken Made

Chicken poop or chicken manure is a very good fertilizer and can be used to treat your lawn (and, indeed, any vegetable gardens that you may have). If you want to use it in large quantities then it’s best to place it in a composting heap and allow it to break down fully because, as will see a little later, highly concentrated chicken poop can damage your lawn.

Most of the time, however, a few chickens running around a lawn can be allowed to poop freely and their manure will simply act as a fertilizer.

Chickens And Wet Lawns: A Warning

Your chickens need water and so does your lawn. However, they shouldn’t get watered at the same time. If your chickens get wet, they risk developing infection and it’s also not very good for their overall welfare – soggy chickens are usually unhappy chickens.

Watering a lawn is akin to a heavy rainfall and even the hardiest chicken hides from heavy rain. If your birds need a drink, give them a drink but don’t spray it all over them and the grass. In fact, it’s best if you keep the chickens of the grass while it’s soaked through.

The Real Danger To Chickens – Herbicides

Weed killers and other herbicides are not a good mix with chickens. They are usually highly toxic and can be absorbed through the chicken’s skin or lungs as well as when they eat anything in your garden.

That means we’d avoid all weed killers in the garden if at all possible, let your chickens eat the weed’s seeds and dig up any weeds as they arise. But we know that occasionally this isn’t going to be possible.

So, if you have to use a weed killer:

  • Don’t use pellets. Pellet weed killers may hang around for days after they’ve been used and are more likely to be consumed by your chickens.
  • Do use sprays. A spray weed killer will tend to be residue-free after about 24-48 hours.
  • Do fence off areas that you’ve sprayed. We’d say for 3 days just to be on the safe side or until the first heavy rain has come.
  • If you must spray, try to do one place at a time. This means you can still let your chickens roam free in the majority of your lawn.

A Natural Herbicide Recipe

Before you turn to chemical herbicides and have to worry about containing your chickens, you might also want to try using a harmless homemade weed killer. It’s not going to have much luck with a giant weed patch established over years but can kill off smaller patches.

However, please remember this is not a selective product and it cannot tell the difference between weeds and other plants, it will almost certainly kill all plants in the area it is used on. So, be careful with it.

The recipe is simple:

  • 1 x Gallon of White Vinegar
  • 1 x Cup of Salt (that’s NaCl and don’t use the Iodized stuff)
  • 1 x Tablespoon of Dish Washing Liquid

This should be placed in a spray bottle and then sprayed over the foliage (that’s the leaves, stems, etc.) and ideally, on the roots as well.

When the weeds die, you should turn your soil over and then remove and dispose of the weeds and water it heavily. If you find the soil is too acidic (a potential problem when you spray vinegar on soil) you can add some lime to bring the PH back to normal.

The Best Way To Safeguard Your Grass and Garden From Chickens

OK, we’ve looked at how fertilizers and herbicides can affect chickens and how chickens can make the best fertilizer, but we should also touch on how to stop your chickens from harming your grass too.

Keep Pollution Away

Chicken poop, as we’ve already mentioned, can be a very effective lawn fertilizer but it’s worth noting that you can’t just use your lawn as a chicken toilet. Fresh chicken poop is very high in nitrogen and in large doses, this can be toxic to the grass. If too much poop builds up in your garden it can end up giving your grass a chemical burn.

However, as long as you don’t let poop build up and allow your chickens to roam all over your garden – it will act as a fertilizer. If you find it building up, you can pick up the pollution or if you’re feeling a bit squeamish about this – you can wash it away with a hose.

Keeping The Number Of Chickens In Check

You need to think carefully about how many chickens your lawn can handle. While farm kids will tell you that they can keep unlimited chickens out back, they will neglect to mention that this land is rarely green and lawn-like but more a muddy brown.

If you take on too many chickens, you’re going to get too much chicken waste building up on your lawn and as we’ve just seen- this can be toxic for grass. So, keep the numbers sensible and make sure that you regularly clean up after your chickens if you want your lawn to thrive.

Let Your Lawn Grow Out

Short grass is more susceptible to nitrogen burns than longer grass, so if you’re at all concerned that there may be too much chicken waste from your chickens for the lawn to handle, you might be able to head off the problem by letting the grass grow a little longer than you normally would.

We’d also recommend that when you do mow the garden – you let the clippings lie. Chickens will be happy to chew the clippings and avoid the live grass which can help avoid the chickens from damaging the roots of your grass.


Is Lawn Fertilizer Safe For Chickens? Yes, it is. However, we strongly recommend avoiding synthetic fertilizers particularly if you are eating the eggs your chickens produce. Don’t forget that chicken poop itself is an excellent lawn fertilizer.

Weedkiller, on the other hand, is not as safe for chickens and you should avoid using it if it all possible and if you must use it, take sensible precautions to protect your chickens.

You can also take measures to protect your lawn from your chickens including not letting their poop build-up, keeping their numbers reasonable and allowing your grass to grow a little longer than before you had chickens.

Here are some of my favorite products for chickens and their coops:

Darren Black

I'm Darren Black, the owner, and author of I am from Scotland, United Kingdom and passionate about sharing useful information and tips about properly caring for an animal's wellbeing.

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