Moving Forward- Breeding for Resistance to Marek's Disease

[feather13]

@microchick : I'm slowly learning as I go, too, but there doesn't seem to be much out there about how to live with Mareks. There's information on how to cull birds with it, veterinary science articles on what it is, and precautions to take to not get it. Your messages on BYC and your article have and will help those of us with it in our flocks to feel less alone (and to be very careful about where to get new birds). Really happy to hear you have three year old vaccinated chickens that are doing well!

How do you like your Egyptian Fayoumis? We got two with our McMurray order and I've been posting a lot about them recently. Wow... they are unlike anything we've ever had. I know chickens are the closest living relative to T-Rexes, but EFs are actual pterodactyls lol. They are the second loudest thing to Howler Monkeys I've ever had the (dis)pleasure of hearing and they are bonkers skittish. We free range our birds during the day and the EFs go into all the neighbors' yards (where they continue to scream), despite the fact that we have 6ft walls with a 10ft drop off on the other side. One of the EFs already got killed by a neighbor's dogs (the dogs bark all day, so it's not like she wasn't warned) and the other peer pressures the standard breed girls to hop over the wall with her. My daughters have named the EFs "Skinny Legends" because they're so bony. They're beautiful, resistant to Mareks, and fiercely independent (always a good trait in a girl!), but I wouldn't necessarily recommend them for suburban backyards unless you like your neighborhood to sound like Jurassic Park lol.

 

[microchick]

As a person who actively breeds for resistance to Marek's.. YES 100% birds that show resistance are still exposed and carrying it IF you have seen it and/or have a diagnosis.

It (Mdv) is stated by the state poultry vet at UC Davis in California to be "ubiquitous" in poultry environments.

The idea is not that we eliminate Mareks but that we breed a better bird..

They MAY still succumb as they AGE with DIFFERENT symptoms than those that appear in the juvenile birds.. IS the newest revelation made known to me via another persons experience/diagnosis.. as our bodies age our immune system declines and what it once fought or controlled well it may no longer continue to do so.. I'm in my 40's and despite having more confidence and skill (mentally) there are some things my body just will not comply with like it did in my 20's.. I have less flexibility and strength (physically). To wit any ELDER bird who start to show symptoms will be culled as quickly as a younger one, in MY "breeding for resistance" program.. there is NO baby the bird along with antibiotics and anticoccidia-stats.. that's NOT resistance.


I'm sorry for your loss.

It has hit hard here this past fall as well.

For you it sounds like ordering vaccinated birds is the right thing to do, which I see you've handled. And a Carolina coop to boot, congrats on your new and happier adventure!

Two minds with the same thought.

I have no illusions about the vaccinated birds that I have brought into my flock of Marek's positive chickens that they aren't exposed to and carrying MD.

And I agree 100% about your observations and experiences in breeding for Marek's resistance. To be resistant to anything, a chicken must be exposed to the contagion and not only survive it, but live to breed chicks that are also resistant.

As for what you notice as you age in your own body.....I hear ya loud and clear!

 

[microchick]

Studies show that exposed birds, even though they survive and are resistant still carry the virus in their dander.

This quote is directly from the Merck Veterinary Manual.

Transmission and Epidemiology​

Marek disease is highly contagious and readily transmitted among chickens. The virus matures into a fully infective, enveloped form in the epithelium of the feather follicle, from which it is released into the environment. It may survive for months in poultry house litter or dust. Dust or dander from infected chickens is particularly effective in transmission. Once the virus is introduced into a chicken flock, regardless of vaccination status, infection spreads quickly from bird to bird. Infected chickens continue to be carriers for long periods and act as sources of infectious virus. Shedding of infectious virus can be reduced, but not prevented, by prior vaccination. Unlike virulent strains of Marek disease virus, which are highly contagious, turkey herpesvirus is not readily transmissible among chickens (although it is easily transmitted among turkeys, its natural host). Attenuated Marek disease virus strains vary greatly in their transmissibility among chickens; the most highly attenuated are not transmitted. Marek disease virus is not vertically transmitted.

End of quote.

Then there is Typoid Mary to consider who was exposed to Typhoid Fever, never developed the disease but spread it to everyone she met because she was a carrier.

Chicken Pox lives on in the host's body, sometimes colonizing at the base of nerves to rear it's ugly head years later as shingles. The only way a person can get shingles is from the herpes zoster virus. Now, shingles aren't catching but if a person who hasn't had chicken pox comes in contact with the fluid from the blisters caused by shingles, then they can come down with chicken pox. Ask me how I know that one....which I learned the hard way and I'm a retired nurse, LOL. Chicken Pox can also be 'silent' in nature. Meaning you can have them and not know you have them. The symptoms might be really mild and you may even not have a rash...once again ask me how I know that one.

To think that resistant chickens cannot spread MD is a misconception of the disease. I will put it this way. IF you have Marek's disease in your flock, confirmed by a medical professional, then your entire flock is carriers of the disease whether or not they show symptoms. Resistant birds are carriers. As I stated earlier, resistance does not mean immunity. Resistance means they are less likely to be killed by the disease then birds that are susceptible.

My Egyptian Fayoumis, while resistant to Marek's Disease, are still carriers of the disease that infected our property. Vaccinated birds while resistant to the disease are still carriers of the disease.

Some breeds of chickens are more susceptible than others. Silkies, Seabrights, Cochins, Buff Orpingtons to name a few are VERY highly susceptible to Marek's Disease. Other birds like Fayoumis and naked necked Turkens are resistant to the disease. The closer the bird is to it's wild state (one of the reasons they suspect a Fayoumi is more resistant than a hybrid specialized breed) is because their genetics are closer to chicken genes in the wild state.

I suspect that Marek's Disease is a byproduct of science and breeders trying to create chickens that produce large amounts of eggs and look pretty while they are doing it.

​

 

[EggSighted4Life]

Some breeds of chickens are more susceptible than others. Silkies, Seabrights, Cochins, Buff Orpingtons to name a few are VERY highly susceptible to Marek's Disease.

Not in MY anecdotal experience.. The Silkies I bred NEVER showed any symptoms and there were a whole lot of them.. I even got reports back that chicks from my stock were the only ones surviving a distant outbreak several years AFTER they had left my place BEFORE any diagnosis and while still freshly incubated... They kept bringing bird from from unknown places plus added in some hatchery sex links.

MAYBE it matters how virulent the time of year is AND at what age they're first exposed..

There was ONE gene identified that actually showed resistance. Whether or not one has that and WHICH gene it was or how it MIGHT effect carrier status.. that I do not personally recall if it had been reported.. It's a lot of information to try and retain.. and requires repeated AND updated review on MY part in order to maintain and semblance of comprehension.

im not sure if I agree that resistant birds (not from the vaccine) are carriers.

I'm not sure if I agree with your take either.. but I do gather what you are expressing and will take the time to look and consider further.

Noting the KEY is discussion towards comprehension and hashing it out in a civilized manner as appears to be going on here!

I see lots fascinating thing to further my over all understanding pertaining to LIFE!

Interesting point.. yes Marek's writes itself into the dna somehow but does indeed NOT transmit vertically!!

Thank you guys for taking the time to express the reasoning behind your comprehension.

 

[microchick]

Whow, @EggSighted4Life where did you get your Silkies? Did you get them from a private breeder? I wonder, if you did if that makes a difference.

I've read that some studies state that chicks from vaccinated hens may get a degree of resistance bred into them but everything I've read states that Silkies have very low resistance to MD.

I was offered a dozen Silkie chicks this past spring and turned them down even though they were vaccinated. I was too afraid my particular strain of MD would hurt them faster than my head pecking hens would.

@jwehl I've enjoyed reading your posts. You offer some really good questions about immunity vs resistance and the disease spread.

You have to remember that viruses can be transmitted long before the host shows symptoms. Look at Covid for instance, some people are highly contagious and never show any symptoms themselves becoming super spreaders of the disease. Think of MD in chickens as operating the same way. A bird can be positive for the disease having been exposed to contaminated dander and survive it's primary infection of the disease but continue to spread the disease in it's dander even though there are no discernable symptoms in the host chicken.

Vaccinating or not vaccinating is a personal decision a flock owner must make and what is right for one may not be right for another. I was losing so many birds at one point in time that I decided that the only way I was going to be able to recover my losses was to try brining in new chicks that had been vaccinated. I don't vaccinate myself. I usually only hatch out a dozen or so chicks a year as I have to consider what space I have left.

For me, vaccinating worked. I don't vaccinate my own chicks that I or a broody hatch out but every chick I buy outside our farm is vaccinated.

For me not to do so would be a death sentence for the chick and frankly, I don't need that kind of karma.

 

[Nambroth]

Good luck to you! I am posting so that I can watch this thread and hopefully glean knowledge. I have a very small flock of very much pet birds, so have not gone down this route, because even one loss is heartbreaking. For those that have less personal attachment to their flock, are willing to cull and keep very strict and good records, and are in it for the long haul.... it is likely a worthwhile venture.

 

[chooks4life]

Thanks so much for your reply chooks4life! Your account is exactly the kind of info I am looking for! I'm glad that you are of a like mind. As for antibiotics, all I have is a coccidiostat. I have not medicated affected individuals. Upon presentation of symptoms they are swiftly culled...infected birds shed the virus, as do any "recovered" birds. It's been most obvious in my flock of youngsters. They range from 8-14 weeks old. It's decimated the speckled sussex I was growing out...it's gotten 6 of 11 so far . They seem to be the most suspectible. It only outright killed a couple, the rest I euthanized myself. The birds were mostly just wasting away...lethargy, inappetance, weak. Though a couple had neck and leg paralysis.

I would agree in that Austrailian diseases are different from those in North America...I would think the strains/severity would vary.

I also use deep litter and lime in my coops. Having works in a horse barn for years, I finally put two and two together and began applying lime in my coop. I have raised a few batches of chicks under broodies this year, but I also have used an incubator. I get my chicks out of the brooder (when using an incubator) and onto pasture as soon as possible. I also supplement the chicks in the brooder with fresh greens from the yard. I have yet to add herbs to my feed, though I have heard that garlic is excellent for them. I'll start adding to to their feed/water. I do not scrimp on their nutrition...though it is a commercial brand. I buy the most expensive feed that I can, though it's Purina and I'm sure all their claims to superior nutrition is a lie.

I have yet to work up the guts and motivation to formulate my own feed.

I am working with pure bred birds...perhaps some of the breeds are weaker because they are kept, propped up, and bred because they look "nice". I hope to make sufficient strides in resistance in a couple of generations...I have read somewhere that MD affects pullets more than cockerels, so I'll have a lot of nice, strong cockerels to breed in the least.

Good to hear.

I agree about Purina and the purebred birds. The weakest animals I've ever dealt with are purebreds. The comment about scrimping on nutrition is due to the commercial layer feeds often being so sub-par in nutrition that they're better classed as survival rations than complete feeds as they're not developed to keep animals alive for more than a few years. They don't supply many minerals, trace element etc which aren't necessary for survival in the short term but which are vital for longevity and total health. The short term deficiency won't show but down the track there's no repairing the harm done, or at least, it's incredibly difficult. The mineral/nutrient mix of many commercial feeds contains between 10 and 20-odd nutrients whereas around 80 is correct for a truly complete feed.

I also saw more pullets than cockerels die from it. That aspect would need investigating I'd guess. There is a reason why, for sure. Haven't heard of one suggested though.

Regarding culling birds showing infection, isn't that a bit of a moot point since by the time one shows infection chances are the whole flock's been exposed? In my experience almost none of mine showed any symptoms but I don't doubt that they've been exposed and are quite likely carriers. I guess it saves you time dealing with the weakest who are most prone, at least. But it also deprives you of a test subject for potential treatments, though it's not imperative that you go along that route anyway. Many paths lead to success.

It's times like these I wish I had a home laboratory, I'd be testing for this and that and ten thousand other things... lol. What's the chances of you finding an open-minded and progressive vet who is willing to help you study this and try to combat it?

I hope this thread yields some hope for Mareks' sufferers in future. I believe you're on the right track, though it won't be easy. Then again the right track rarely is.

Very best wishes with your endeavor.

 

[seminolewind]

Quote:
People should learn all about Marek's before they think they can teach others.
What really gets me mad is people who say that ******** cured their chicken from Marek's. Then they tell everyone that this cure works. Every time I hear that I want to choke.

 

[microchick]

Welcome. Sorry that you are experiencing problems but rest assured that you are not alone.

This is my first surviving venture into breeding for resistance.

This past spring, I purchased 5 Egyptian Fayoumis. One Rooster, 4 pullets. They are thriving. I wasn't planning to set any eggs from them until next year but one accidentally found it's way under a broody hen and voila! A chick was hatched!

His sire is a Amish barnyard bantam cross. Mom a EF pullet. Sadly, his sire died not long after the chick hatched. As he was only two years old, I suspect he was my lone Marek's victim this spring and summer.

After doing a lot of soul searching I made the decision this spring to cull what was left of my original flock. They were not laying much any more. The second generational survival rate was horrible and I couldn't coax them out to free range so other than them sticking around to shed Marek's laced dander, they went to freezer camp.

I plan to add more Fayoumis this spring. They aren't cuddly friendly birds but by golly, they are Marek's resistant and that's all that matters to me! Hopefully "TJ" will be the first of many crosses that will genetically strengthen my barnyard mixes that are showing resistance.

 

[drumstick diva]

There is/was a lady from Alberta, Canada that said she had Mareks in her flock and bred it out of her birds. Tara has/had a thread called, I believe "J'est Another Bird in Pair A Dice." She moved on to Facebook but, her old thread should still be on BYC. I think her last post was around 12-18-18.

I believe her last name was Higgins. or Wiggins. Give me a break, I am old. She bred Chanticleer chickens with the flattest of combs to prevent frost bite, she also had ducks, geese, hair sheep, I think a pair of black swans, Australian Cattle dogs.

I would NEVER go to FB but, I miss her wisdom and wit and wish she would come back here.
I may be mistaken (it wouldn't be the first time) but I believe she and Microchick stay in touch.