The Accidental Smallholder Forum

Livestock => Poultry & Waterfowl => Topic started by: TyIsa on July 20, 2021, 02:40:26 pm

Title: Vision problems in chickens ? Mareks
Post by: TyIsa on July 20, 2021, 02:40:26 pm
I have 2 chickens that have recently developed vision problems. They are ex commercial  dark egg laying Marans type hens and I've had them a year so I suppose they are coming up to 3 years old. 
One hen is very slow and does a head flicking movement that makes me think Marek's but surely an ex commercial bird would have been vaccinated against this?  She first become ill while broody but she managed to successfully raise her chicks and these are now 12 weeks old. Her eyes look normal to me but  her vision is definitely deteriorating. I did a faecal egg count when she first became unwell which didn't show anything accept coccids and as there are no symptoms of coccidiosis in her or the rest of the flock I don't think that is the issue.
The second hen has visibly cloudy eyes and often stands with eyes closed. Other than that she lays, eats and gets about normally. The rest of the flock of 15 chickens of various breeds and ages all seem very healthy.
Really thinking I will have to euthanase these 2 girls but I'm so reluctant as they are  managing to eat and even lay. If it is Marek's - what does this mean for the rest of my flock?
Title: Re: Vision problems in chickens ? Mareks
Post by: twizzel on July 20, 2021, 03:14:02 pm
Could be mycoplasma ? My only experience of mareks was it killed a bunch of pullets I bought in, they all went off their legs.
Title: Re: Vision problems in chickens ? Mareks
Post by: TyIsa on July 20, 2021, 03:36:32 pm
Just looked up mycoplasma - I think they'd have discharge from their eyes. Your description of Mareks sounds typical - young birds, leg paralysis. Mine are slow and do funny head movements but not paralysed.
Title: Re: Vision problems in chickens ? Mareks
Post by: chrismahon on July 20, 2021, 04:44:52 pm
Most likely to be a breeding problem I think. They are only bred to last 18 months, so any future problems haven't been eliminated. I'd certainly not breed from them any only pts if they actually can't live a life anymore. That's very sad as we have two Marans (from France) that are perfectly healthy, laying and are coming up to 5 years old. Must be in-breeding in the UK and my guess is trying to make money by breeding from pullets- disgraceful!!!
Title: Re: Vision problems in chickens ? Mareks
Post by: TyIsa on July 20, 2021, 04:58:53 pm
I'm inclined to agree it's likely a genetic issue -  i had hoped for better from these birds as they are so different from your typical ex commercial Warren type.  Who's ever heard of commercial hens going broody?!  Such a shame as they're beautiful  birds laying really dark brown eggs.
Title: Re: Vision problems in chickens ? Mareks
Post by: twizzel on July 20, 2021, 09:03:26 pm
I'm inclined to agree it's likely a genetic issue -  i had hoped for better from these birds as they are so different from your typical ex commercial Warren type.  Who's ever heard of commercial hens going broody?!  Such a shame as they're beautiful  birds laying really dark brown eggs.
I had a couple go broody once, they hatched out a few chicks each  :)
Title: Re: Vision problems in chickens ? Mareks
Post by: SallyintNorth on July 20, 2021, 10:44:29 pm
Who's ever heard of commercial hens going broody?! 

Everyone who has ever had any kept naturally
Title: Re: Vision problems in chickens ? Mareks
Post by: Scarlet.Dragon on July 21, 2021, 10:03:58 pm
Just attended a really good webinar on chicken keeping - it will be available as a playback option in due course for anyone who missed it where Mareks was mentioned.  Interestingly the vet talking about it reckons Mareks is over-diagnosed and having done a number of PMs on birds that were diagnosed with Mareks the majority were negative.

She indicated that Mareks predominantly affects young birds around POL and that for the majority of ex-commercial/older purebreds with similar symptoms Mareks was not a factor. 

Also interesting that vaccination for Mareks doesn't prevent them getting it, it merely suppresses the symptoms meaning they can be 'silent carriers' if mixing with unvaccinated stock.
Title: Re: Vision problems in chickens ? Mareks
Post by: TyIsa on July 22, 2021, 04:08:57 pm
Thanks Scarlet dragon, that's really interesting. I notice on the local Facebook chicken forums here people are very quick to 'diagnose' Marek's without much evidence.
I know you are not supposed to mix vaccinated and unvaccinated chickens because of the risk of the vaccinated birds being asymptomatic carriers of Marek's, however this is something I have done without problems for many years (always have a few hybrids and ex batts amongst my home hatched stock). If it is Mareks in these two, it has not affected any of the others so I assume they must have good natural immunity.