Signs of Worms in Sheep (and How to Treat Them)

As a sheep farmer, you need to be able to recognize the sign of worms in sheep as early as possible.

Not only does a parasite overload kill your flock, they are also a big reason why your herd won’t grow as quickly.. 

Managing the parasite load in sheep is critical for your success as a sheep farmer.

Recently, we hired someone to care for our sheep for several months, as we were going away for a while. This was great for us, but not so good for the sheep.

The hired hand took good care of them, but because we were not at home for extended periods of time, we did not catch the parasite problem right away. 

Once we were back home, my husband immediately recognized that two of our ewes were not feeling well at all. They had bottle jaw and were looking weak and unhealthy.

Because we were approximately two months away from lambing, this was not a good sign at all.

My husband immediately gave them Ivermectin, and it helped. We do not know if they will have lambs come April, but they are looking healthier already. 

Had we realized the worm problem earlier, we could have been more aggressive with not letting the parasites become a bigger problem.

It’s a fact of sheep farming. You will need to manage the parasite load.

Regenerative practices and proper management will make a big difference in the health of your flock, but this requires learning new techniques and ways of doing things.

Interested in more Homesteading and Gardening Content? Follow me on Instagram!

How to Prevent Worms in Sheep

This post might contain affiliate links. If you purchase anything through links on my site, know that I receive a small commission at no extra cost to you.

As with everything else, the prevention of parasites in sheep is the best cure..

Proper practices can sufficiently prevent worms in sheep, to the extent that you don’t need to worry about treating them at all.

However, this can often be very difficult as enough grazing space is needed to keep worm populations low. 

Prevent worms in sheep by giving them high-quality feed, making sure they have access to minerals, as well as giving them enough space.

Well-nourished sheep will have less of a parasite problem than weak and unhealthy sheep. 

Start with A Resistant Breed

Jacob, Icelandic, and any of the old, unimproved breeds usually have little problems with parasites. Research before buying.

Sanitation Critical

Feed should never be placed on contaminated ground or bedding. Creep feeders and water tanks should be kept clean and free from the sheep droppings. 

Low Population Density

When the population on a given field is low, sheep get better quality feed, but they also deposit fewer eggs. Therefore fewer larvae will develop. 

Don’t Overgraze

When sheep are overgrazed, they are forced to graze close to the ground in order to receive their feed. This causes them to ingest more larvae. Implementing regenerative soil practices is a great way to prevent worms in sheep.

Feed them High Quality Food

Sheep that are fed better are stronger and are better able to fight against the parasites. Unhealthy sheep can not tolerate as much of a worm burden as those that are healthy.

Mineral Blocks

A lack of the right kind of nutrients, not enough protein, and a lack of vitamins will leave them more susceptible to worm damage.


This is a diagnostic test that helps producers identify whether or not the sheep has worms.

It can help eliminate unnecessary deworming and therefore unnecessary drug-resistant parasites.

Signs of Worms in Sheep


This is usually the first symptom, although it can be hard to catch. Sheep with the very pale, grayish color of the inner and lower eyelids show signs of a worm infestation. 


Diarrhea is sheep is never a good sign. Sheep usually have small, dark pebbles as feces, and when this turns to liquid, chances are the small, brownish worm ‘Ostertagia’ is at fault. 


Coughing is another symptom of a worm infestation.

Weight Loss

You don’t want your sheep too fat, but when you start noticing a loss of fat and muscle tone, suspect parasites.


A sheep that is thin, and yet has a big belly most likely has worms as well. If sheep that are not pregnant, look like they are, then potbelly is what you are seeing. 

Wool break

When the fleece of your sheep starts falling out at the roots, it will make her appear motley and disheveled.

There are some types of sheep that shed their wool in spring, but if you do not have one of these breeds, the wool break is a sign of worms.

Bottle Jaw

One of the last symptoms to appear, bottle jaw tells you that the parasite infestation is very bad already. Consider it your final warning that the worms are severe enough to kill your sheep.

How to Treat Worms in Sheep


Using parasiticides is a very common practice among sheep farmers, but more and more are realizing that drug-resistant parasites are becoming a problem.

This is happening a lot quicker than producers often consider so a more effective and sustainable way is needed. For organic and regenerative, a more holistic way of dealing with worms in sheep is needed.

Parasitics are effective when used wisely, and it is a good idea to contact your vet for help. 

Common Dewormer for sheep

There are several types of dewormer in the ivomec kind, including Biomectin and Febendazole.

We have used a form of ivermectin so far on our farm and it has helped, but are always on the look out for other ways to manage parasites more naturally. 

Ivermectin Sheep Drench

You can buy it here.

Agrilabs Prohibit Soluble Drench Powder – Drench for Sheep

You can buy it here.

Patterson Veterinary Cydectin Oral Drench Wormer Sheep

You can buy it here.

Holistic Practices

Below are some ways of controlling the worm population in small ruminants holistically.

Natural Ways of Deworming Sheep

1.Graze them on Forage Chicory.

Numerous studies have documented that certain compounds in forage chicory have harmful effects on internal parasites in sheep. It significantly reduces the worm burden, as well as improved animal production. 

2.Molasses on Wormwood

You can buy this dried, and we haven’t personally tried this yet but would love to. Be careful with wormwood as it can cause a mamma to stop lactating.


Garlic Barrier is a product someone developed for this product, and is recommended by regenerative farmers.


Letting the sheep graze near pine trees has helped some farmers lower the worm burden in their flock. 

We have yet to try these to help manage the parasite load in our sheep, and we are learning along with you. This article has more information that you might find useful.

5.Basic H

“Basic H is a non-ionic surfactant (not organically approved) that is added to the sole source of drinking water at 1 cup of Basic H to 100 gallons of water. Animals need to be confined to the water source for two days. Treatment is repeated six times yearly.” source

6.Molly’s Herbal Wormer

Formula one contains four herbs, including wormwood, while formula two contains six, and does not contain wormwood (better for pregnant and lactating ewes). You can buy it here.

As organic or regenerative farmers, we need to learn to live with parasites, and learn to manage them well instead of trying to kill everything.

Proper field rotation, and keeping an eye overall on your sheep should eliminate the need for deworming as often, but the reality is that you probably will have to at times.


As farmers that don’t like to use non-organic treatments, we need to remember that its best to treat our livestock rather than sacrifice their health.

The signs of worms in sheep can be easy to miss, but in order for your flock to grow and be profitable for your farm. Several early symptoms that you want to catch are anemia, coughing, and scours.

If your sheep starts showing symptoms of bottle jaw, and a potbelly, know that help is needed fast or the sheep will die. 

Taking good care of your sheep goes a long way for the health of your flock. What has helped you when you have signs of worms in your sheep? Let me know in the comments below.

Taking good care of your sheep goes a long way for the health of your flock. What has helped you when you have signs of worms in your sheep? Let me know in the comments below.

4 thoughts on “Signs of Worms in Sheep (and How to Treat Them)”

  1. I really love reading and I appreciate your advice, I have recently taken up the keeping of Barbados sheep on my acre of property in hockley Texas, I am new to sheep keeping so any advice I can get is greatly appreciated!

  2. Yay! That’s so exciting. Sheep are amazing. One tip I can give you is prevention is key. Keeping a flock healthy is easier than getting a sick flock healthy. Make sure your sheep have access to minerals.

Leave a Comment

Your email address will not be published. Required fields are marked *