Do I have a mareks positive flock?

[georgiashens]

Hello everyone. I have a flock of 4 hens and although they all seem in pretty good shape, one of my girls, Holly the cream legbar, has oddly shaped pupils that are different sizes. She’s also pretty underweight. I can’t tell from looking at the pictures if they are greying or not and if it is I’m not sure how to go about testing (uk) or managing. If she’s showing symptoms with her eye now, does that mean she will eventually succumb to this disease? Any help would be greatly appreciated. Thank you!

 

[Chicken_Obsesser]

@azygous

 

[azygous]

Very suspicious eye presentation pointing to ocular Marek's. Of course, you would need to have an animal lab test her, and it's more accurately done postmortem to examine tissue for the virus.

Yes, ocular Marek's can sometimes develop into the paralytic form that causes nerve inflammation and tumors.

 

[georgiashens]

Very suspicious eye presentation pointing to ocular Marek's. Of course, you would need to have an animal lab test her, and it's more accurately done postmortem to examine tissue for the virus.

Yes, ocular Marek's can sometimes develop into the paralytic form that causes nerve inflammation and tumors.

Thank you for your reply, I did some digging and found a picture from one of my other hens breeder of a chicken with an odd looking eye. I’m just wondering if this could be mareks? Would then make sense why she has it…

 

[Eggcessive]

I would say that it does look like ocular Mareks as well.

Thank you for your reply, I did some digging and found a picture from one of my other hens breeder of a chicken with an odd looking eye. I’m just wondering if this could be mareks? Would then make sense why she has it…View attachment 4130615

 

[coach723]

Picture of the second bird is too blurry to determine. I would agree that I would suspect occular marek's may be the issue with yours. Not all birds will present with a completely grayed iris, sometimes it's just a narrow gray band and the pupil will gradually shrink down to a pinpoint. There are also usually changes to the way the iris looks, even it it doesn't gray out, which I think your birds eyes have. I've had birds with occular marek's live for years before finally sucumbing to it. The only way to know for sure is testing. There is a lab in Texas that does it with a blood sample, but since you are in the UK, shipping times probably make that not doable. As said before, most of the time it's confirmed post mortem. If it is Marek's then the flock has been exposed and some birds may present with the visceral or neural form as well, it's hard to predict. I will attach a couple of pictures of my birds with occular Marek's below.
This was a roo that lived about 18 months once symptoms showed up, he eventually passed from visceral tumors.

This bird is still living now, it's been over 2 years since she started showing pupil changes, but she is starting to slow, she is completely blind now:

 

[georgiashens]

Picture of the second bird is too blurry to determine. I would agree that I would suspect occular marek's may be the issue with yours. Not all birds will present with a completely grayed iris, sometimes it's just a narrow gray band and the pupil will gradually shrink down to a pinpoint. There are also usually changes to the way the iris looks, even it it doesn't gray out, which I think your birds eyes have. I've had birds with occular marek's live for years before finally sucumbing to it. The only way to know for sure is testing. There is a lab in Texas that does it with a blood sample, but since you are in the UK, shipping times probably make that not doable. As said before, most of the time it's confirmed post mortem. If it is Marek's then the flock has been exposed and some birds may present with the visceral or neural form as well, it's hard to predict. I will attach a couple of pictures of my birds with occular Marek's below.
This was a roo that lived about 18 months once symptoms showed up, he eventually passed from visceral tumors.
View attachment 4130674
View attachment 4130679
This bird is still living now, it's been over 2 years since she started showing pupil changes, but she is starting to slow, she is completely blind now:
View attachment 4130682
View attachment 4130683

Thank you for your response, it’s great to hear from someone with a mareks positive flock. How do you deal with it? I have a few questions if you don’t mind!

Do you still bring new vaccinated birds in and if so, is it cruel to subject them to that in your opinion?

How many of your birds have ended up getting it and were they vaccinated?

How do they usually die?

How do multiple types happen in one flock? Are they all connected or would it be a new strain that’s added?

Here’s a picture of how her eye has progressed in the last month or so:

 

[coach723]

Allowing for different lighting, it does appear that it has progressed in that time frame.
Whatever strain(s) I am dealing with have been relatively mild. I have yet to have a paralyzed leg bird. The one in my second pictures does pick her feet up high, and kick them a lot, I am assuming some kind of nerve involvement that makes her feet feel odd. But she gets around fine, finds her food and water (she is in a smaller run so that she can't really get lost) and other than not being able to see, functions pretty normally.
When I first found I had Marek's in my flock my heart sank and I thought that was going to be it, no more chickens. Once I'd had time to really absorb it all, and calm down, I read absolutely everything I could find on the disease, and on the vaccine. Even though some is contradictory, and as I've learned, not every bird presents like the literature, there is a wealth of information. It takes a while to digest it all. The vaccine is somewhat controversial since it doesn't prevent the bird from contracting the disease, it just reduces mortality from it. They can still get it, can still transmit/spread it, can still die of it in some cases. I don't advise for or against it because we all come from different places, have unique ways of doing things and living with our birds, have different belief systems and values. I always say, read as much as you can, educate yourself as much as you can, and make a choice based on what works for you. There isn't one blanket right answer for everyone. I choose to not vaccinate, or bring in vaccinated birds. I usually hatch here, from non symptomatic birds, working to get birds that are more resistant to the disease. That is a long term project obviously. Initially I lost several birds in succession, it was pretty depressing. But it tapered off to only an occasional one. I have one bird left (besides the hen pictured above) that has occular symptoms. So far, no others currently are showing signs. I did bring in some Egyptian Fayoumi's 2 years ago as chicks (unvaccinated), as they are supposedly more resistant to the disease, in the hope they could pass that into my flock (And I'm gonna say, they are definitely not for everyone!). I hatched for the first time this year, making sure all birds were asymptomatic, I don't think I got any mixes, the fayoumi's all stuck together! I did get two more boys, so hopefully they will gather a mixed harem. We will see. I've lost a couple to predators, but so far none of them has shown any symptoms.
But I completely understand why many choose vaccinated birds. Some strains are certainly more virulent than what I've dealt with, with higher losses, and I understand the heartbreak of losing them to something that you can't do anything about once they have it. I've probably lost about a dozen birds, maybe a few more. I do my own necropsies and sometimes there just isn't space in my day to get one done. I always do if there are questions about what it was. I still lose hens to reproductive problems that have nothing to do with Marek's as well. I made a thread awhile back with some images from a necropsy of a bird that I lost to Marek's. She was seemingly fine, went quickly downhill within a week, and was full of lesions. If you want to look that thread is here:
https://www.backyardchickens.com/threads/necropsy-photos-graphic-mareks-disease-for-info.1525851/
Different birds in the same flock can have different symptoms and different presentation. Immune systems are different, genetics are different. It's impossible to predict how long they can survive. With occular symptoms, many of mine have lived for quite a while. With the visceral form, not so long and often I don't know until the end, they hide it so well.
Being a virus, Marek's does what all virus's do and it mutates. There are numerous strains, and it's impossible to know if you have one, or more, and which ones. I don't even think the labs determine which strain, they just confirm Marek's. That is one question that has been raised about the vaccine. Since the birds don't die as often, but still can pass it to others, is it allowing mutations that make it worse? I don't know the answer to that.
Marek's is far more common than most people realize, but it isn't an end to chicken keeping unless that is your choice. There are many of us that have Marek's positive flocks and still have success. It just changes some of how you do things, and maybe some of the decision making. I don't let sick birds suffer. I will try to treat some things, and if it's not getting a response, I won't let them linger with it.
This is a good article written by a member here, my experience has been very similar to hers.
https://www.backyardchickens.com/ar...-i-learned-to-deal-with-mareks-disease.76944/