Hatching Fertilized Eggs in Flock Potentially Infected with Mareks?

[mrsmistoffelees02]

Hey everyone,

I am preparing to grow my flock in spring. I just expanded my run and am looking forward to adding more variety to my flock.

However, recently it has been brought to my attention that one of my breeder’s other customers had chickens who tested positive for Mareks. While they could have picked it up somewhere besides the hatchery, I have had several chickens unexpectedly die in my short time of keeping them. I wouldn’t be surprised in the least if they tested positive for Mareks also, but I wouldn’t have known if she didn’t have a necropsy on her chickens. However, my birds are all happy and healthy, so I think the ones remaining have immunity to it. I know it is an extremely common disease and most flocks have some strain or another. My chickens are very much my pets, so culling and starting over with vaccinated chickens isn’t something I will consider.

I wanted to allow my broody chickens to hatch fertile eggs instead of getting vaccinated chicks so the integration process is easier. Is this a bad idea? Should I just get extra eggs so the likelihood of more chicks surviving is higher?

 

[azygous]

You can safely hatch eggs from a Marek's infected flock. However, once the chicks hatch, they will be exposed to the virus if your flock carries it. If your flock carries the virus, the chicks may then begin displaying symptoms at around age three months.

The safest course is to incubate the eggs and vaccinate the chicks upon hatch, wait two weeks for the vaccine to work to encourage resistance, and then start introducing the chicks to the flock.

Or, if you feel lucky, if you feel the odds are in your favor that your flock does not carry the virus, go ahead with the plan to give the eggs to your broodies to hatch and raise. I would do this myself in your place, since you have no evidence of Marek's in your flock. If the chicks become symptomatic at ten to twelve weeks, then you will have confirmation that you have a Marek's flock.

Which avenue you pursue will be based on how comfortable you are facing these odds and possible consequences. Either decision is yours alone, and either is a valid one.

 

[Auntiejessi3]

@bhawk-23 may have some very helpful and knowledgeable advice for you.

 

[Sussex19]

Just one thought, if you want vaccinated chicks raised by a broody, you could buy them, and then slip them under your broody.

 

[Egghead_Jr]

There are symptoms to Mereks. A few birds flopping without warning is not one of the symptoms. Most flocks do not have it.

https://extension.psu.edu/mareks-disease-in-chickens

 

[bhawk-23]

I am dealing with conformed Mareks. We also chose to not cull. My first suggestion is to do a necropsy if you have any more girls pass away.

Our first decision was to close our flock and not add anymore. But after losing so many we decided to attempt 5 vaccinated chicks.

We kept them inside for about 5 weeks and then put their brooder coop inside the larger coop. They just turned 16 weeks and I am noticing some concerning symptoms in one (possibly 2) who will need to be watched closely.
We chose vaccinated chicks to give a “better” chance of staying symptom free.
But if your flock seems healthy and good then hatching might be ok. I do agree with @azygous that if you have mareks you will surely find out with the chicks. You need to be prepared for this.

What symptoms did your other hens have before dying? In the beginning our hens that died from mareks declined quick, some seemed to be less than 24 hours warning.

 

[bhawk-23]

There are symptoms to Mereks. A few birds flopping without warning is not one of the symptoms. Most flocks do not have it.

https://extension.psu.edu/mareks-disease-in-chickens

I read through the article. Good info on myths and about the vaccine and chicks.

I respectfully disagree about chickens always showing symptoms. Our first bird declined in 24 hours. When we had her necropsied it was noted that the pullet was in great body condition. She had tumors on her organs that eventually killed her. But she was out free ranging with the others up to her death. I noticed her resting more the evening before but she ate, drank and went to roost with the others. The next morning she needed to be euthanized, which is why we brought her to be necropsied. I’ve lost 3 to seizures, who also declined quickly but 2 still had good body mass and the others I can only assume tumors as they also declined and were euthanized within 24 hrs or less.

There are different strains. Mine have not presented with paralysis before passing. We’ve had two necropsied to confirm.

Edited to add that the full sized birds have had internal organ tumors and the 3 bantams had seizures. Not sure why that is but thought I’d mention it.

 

[mrsmistoffelees02]

You can safely hatch eggs from a Marek's infected flock. However, once the chicks hatch, they will be exposed to the virus if your flock carries it. If your flock carries the virus, the chicks may then begin displaying symptoms at around age three months.

The safest course is to incubate the eggs and vaccinate the chicks upon hatch, wait two weeks for the vaccine to work to encourage resistance, and then start introducing the chicks to the flock.

Or, if you feel lucky, if you feel the odds are in your favor that your flock does not carry the virus, go ahead with the plan to give the eggs to your broodies to hatch and raise. I would do this myself in your place, since you have no evidence of Marek's in your flock. If the chicks become symptomatic at ten to twelve weeks, then you will have confirmation that you have a Marek's flock.

Which avenue you pursue will be based on how comfortable you are facing these odds and possible consequences. Either decision is yours alone, and either is a valid one.

Thank you for your response. I really appreciate this. This is kind of what I figured but I haven’t hatched eggs before and I just heard about the Mareks possibility, so I wasn’t sure.

As far as Mareks goes,
I haven’t done any necropsies on my chickens that have died, but I did lose 3 back to back in November. They were around 5 months old. Is that a known age for Mareks to strike? Online reading just said death occurs between 6-30 weeks of age, I’m just trying to figure out why I lost one after another. Their deaths are the only reason I have to believe that it could be disease. It started with sudden weakness and lead to lethargy, then they passed about 2-3 days after onset of symptoms (even after attempted treatment with isolation, scrambled egg, and Nutridrench). However, the rest of my flock has been fine.

 

[azygous]

Marek's doesn't usually involve sudden death. It usually produces symptoms at ten weeks. There may have been something the chickens were exposed to, a bacterium, a toxic substance, etc, that killed them. At this point, it's not possible to track it down.

My reasoning is that if you have Marek's in your flock, introducing chicks will confirm it or eliminate the possibility if they survive to adulthood.

This strategy would be irresponsible only if you have had chicks become symptomatic at ten weeks and eventually die after severe paralysis. To the contrary, you have no real evidence of Marek's being in your flock other than these sudden deaths, and they don't fit the Marek's pattern.

 

[mrsmistoffelees02]

Marek's doesn't usually involve sudden death. It usually produces symptoms at ten weeks. There may have been something the chickens were exposed to, a bacterium, a toxic substance, etc, that killed them. At this point, it's not possible to track it down.

My reasoning is that if you have Marek's in your flock, introducing chicks will confirm it or eliminate the possibility if they survive to adulthood.

This strategy would be irresponsible only if you have had chicks become symptomatic at ten weeks and eventually die after severe paralysis. To the contrary, you have no real evidence of Marek's being in your flock other than these sudden deaths, and they don't fit the Marek's pattern.

I see what you are saying. Thank you for your advice. It’s nice to know the deaths don’t fit the Mareks pattern - that was the only thing I could reasonably conclude. I think I will try this. I suppose it couldn’t hurt to try some vaccinated chicks as well as hatching eggs and hope for the best outcome. Experience is the best teacher!