Chickens Stopped Laying due to Worms

This week, I find the reason my chickens have stopped laying is due to them carrying roundworms.

I moved my chickens into their new runs at the end of last year and had treated them with Flubenvet wormer as I always do around October / November time. I treat my chickens routinely every 6 months or so unless I suspect a problem and normally use a combination of other herbal solutions and treatments in between times.


My half a dozen Light Sussex pullets laid very well over the winter months and over Christmas and the New Year, I was getting 7 eggs per day from my total of 13 hens / pullets mixed, which considering the awful wet weather we were having and the mud in the field, I felt was pretty good for the darker months.

As February arrived and the days were starting to become longer, I expected more hens to start coming into lay, but this didn’t happen. In fact, the reverse happened, the number of eggs started to decrease. I thought this was strange but decided to be patient, waiting to see if the chickens would come back into lay as the daylight hours increased further.

Last weekend, I decided that there was definitely something wrong in the flock. Normally, at this time of year, every hen is laying and we are over run with eggs. We were getting 3 or 4 eggs per day from the 13 Light Sussex hens. I couldn’t understand what the problem was though. The hens were getting a good diet, sufficient protein and were free range across quarter of an acre. There were no red mites to be seen in their coop (it is still too cold, except for the very odd day for red mite to be active) and they weren’t stressed in any way.

It took a little while, however I believe I have got to the bottom of the problem. Worms. In fact Large Roundworm to be precise.

Chicken Roundworm
Large Roundworm in Dropping

The Large Roundworm is one of the most common worms to infect poultry and are very easy to spot in droppings due to their 5 to 8cm size. They look like small pieces of spaghetti (sorry, you’ll never eat spaghetti bolognaise again now). The trouble is, only a worm-count will identify their eggs in droppings (which are shed by the thousand) so unless you are lucky enough for an odd worm to come out in a dropping or your birds are so heavily infested that the same thing happens – AND – you spot it, you won’t really know your birds are infected.

I treated my flock with Flubenvet 2.5% wormer (there is also a 1% 60g pack if you have 20 birds or less). When you do this, it can be interesting to put newspaper in the coop under their perches for a couple of days after the first treatment and have a look what comes out. In my case, it was fairly easy to see the odd one or two in droppings in the run.

Roundworm take the ‘direct’ infection route, that is, chickens pick up eggs from the ground and ingest them (rather than the indirect route where the egg is picked up by an insect such as an earthworm and the chicken becomes infected by eating the insect). Roundworms have a prepatent period of 5 to 10 weeks, this means that although Flubenvet kills all of the worms and their eggs, my birds could pick up infective eggs after their treatment and get re-infected. In 5 to 10 weeks time, these will be adult, egg laying roundworm so I should treat my flock with Flubenvet again before this time – so about a month from now should be ideal to make sure I kill off any worms before they can lay thousands more eggs.

So this is most probably the reason my chickens stopped laying. The rest of my birds are going to be treated with a the wormer now as a precaution, even though they are laying well.

You can read more about worming chickens here:

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Tim Daniels

Tim is the founder of the poultrykeeper website and lives in Herefordshire, UK. He keeps Cream Legbar chickens, Silver Sebright bantams and hybrid layers for eggs, Abacot Ranger ducks, Brecon Buff geese and some quail.

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