When hens become penguins

Posted 9th July 2015 09:20am by

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 too.  Your ex-bat 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 she enters her well- earned retirement and the pressure is off she may change her laying pattern and it is not un-common for a hen to go off lay for a period time.  It is important that you get to know your hen and what is normal for her.

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

Now for the technical part… 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 – you will all have heard your hen announcing this fact at the top of her voice!

Occasionally the yolk will 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 but 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.

The yolk material is a rich growing medium for bacteria which can cause the blind layer to go on to develop egg peritonitis.  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.

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.  This is not suitable for every hen, but worth considering if your hen is otherwise in good health.

Spaying your hen is another option (the abdomen is flushed at the same time to remove yolk material)., although this is a fairly specialized procedure and also carries anaesthetic risks.

Visit our Hen Health page for more advice, view our Hen Examination Guidelines or click here to Find Your Nearest Hen Friendly Vet.

If you would like to ask Gaynor a hen health question please email gaynor.davies@bwht.co.uk or call Hen Central on 01884 860084.

To support our Advice Line we ask for a nominal donation to help fund this service, so that we can continue to help your hens.