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What is egg yolk peritonitis?

If you’ve ever seen one of your hens waddling around like a penguin it may well be that she was suffering from egg yolk peritonitis. 

Of course, a waddle could be a sign of many other things, but usually it relates to your hen’s egg laying and could be an indicator of an underlying issue. 

Our hard-working commercial hens are selectively bred to be the best at what they do – laying eggs, and they are very good at it indeed.  Your ex-commercial hen will have been popping out one egg every 22-25 hours since she started work as a 20-week-old point of lay hen.  

As your hen enters her well-earned retirement and the pressure is off, she may change her laying pattern and it is not uncommon for a hen to go off-lay for a period of time.  It is important that you get to know your hen and what is normal for her as every hen is different. 

If your hen is laying, her vent will be shaped like a slot, much like a money box, and her comb should be plump and red. A hen that is off lay will have a round vent. You should compare a couple of your hens to help you recognize the difference. 

Egg yolk peritonitis – the technical bit 

Hens will produce an egg (mostly yolk at this stage) from the ovary, which will pass into a funnel known as the infundibulum. The egg passes through various stages and the shell is added before exiting the vent – at this stage, you will all have heard your hen announcing this fact at the top of her voice! It can be a very noisy process! 

Occasionally the yolk can miss the funnel and drop into the abdominal cavity. This can be due to a few different factors including exposure to infectious bronchitis in earlier life.  Believe it or not, the cells in the respiratory tract are not dissimilar to those in the reproductive tract. 

Mostly the yolk will be scavenged and absorbed by the body’s defences. However, continued internal laying will result in a build-up of yolk material in the abdomen. This hen is known as an internal or blind layer. A blind layer can lead a happy life but will benefit from a corn only diet to try and stop her laying. Feed and water containers may need to be raised to allow her to eat and drink more easily and your coop will need to be checked for ease of access. 

Egg yolk peritonitis treatment 

The material that the yolk is made of is a rich growing medium for bacteria which can cause the blind layer to go on to develop egg yolk peritonitis or EYP for short. A course of antibiotics can be beneficial to treat the infection, but this will not stop the process of yolk building up. Blind layers are classically described as having a wide leg stance, and often resembling a penguin in appearance – this explains the waddle! 

Penguin hen Egg Yolk Peritonitis
This hen’s penguin-like stance indicates she is suffering from egg yolk peritonitis.

A hormone implant (Suprelorin Virbac) is available from your vet. It temporarily takes your hen off-lay and allows her body defences time to scavenge some of the yolk material. It should be said that this is not suitable for every hen, but it is worth considering if your hen is otherwise in good health. 

Another option would be spaying your hen. This is where the abdomen is flushed at the same time to remove yolk material. However, this is a fairly specialized procedure and also carries anaesthetic risks. Remember, you should always consult with an expert such as your nearest hen-friendly vet as to whether this option is something you wish to proceed with. 

For more support on this please call our Hen Helpline on 01884 860084. 

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