Marek's...or is it?

I have a question for people here who may have more chicken experience than I do. This summer I lost a bunch of young birds to a condition I wrote off as Marek's, but now I am not so sure.

One by one the birds seemed to lose control of their legs. The legs seemed unable to support the bird. Eventually the bird died, emaciated due to their lack of ability to reach the food and water. I began culling at the first sign of this issue. I didn't like to watch my birds starving to death. One, an Ameraucana, seemed more robust than the rest. She was always near the food and water, and in spite of being unable to move she kept her weight, so I let her live.

Over the past three weeks she has gradually regained use of her legs and is now walking around very easily! Now I am doubting my amateur diagnosis of Marek's. I didn't think they could recover. Am I wrong? Or is there some other chicken leg paralysis disease out there?

Sounds like Marek's to me. I've had exactly the same thing happen. Birds vary greatly in their susceptibility to Marek's; some die quickly, some die slowly, and some recover completely.

Ipf, I recall a previous conversation about Marek's. The ones who did not get it may have a natural immunity. What about those who get it and recover? No, I suspect?

Dang, good discussion. I think from my understanding of mareks disease is that some recover, but they are definitely carriers. The symptoms are in limbo. I really wish there was more understanding of this disease. I think that unless we are hit with it, we really do not understand the entire disease itself. Probably would be nice to hear an authority on it. I cull, if I ever see that sign of any wrecked leg or wing that does not work. I have a tough love and if I even think that some bird may have something that could be passed around, it is gone immediately. Only experienced, what I believe to be marek's a couple of times. But really, I think if a bird recovers from marek's it is a carrier. could be wrong, but memory of what I have read concurs with my sometimes foggy memories of what I have read. would love to hear more comments. Someone know for sure? Have an awesome day, CynthiaM.

ALL your birds have been exposed to Marek's; it's everywhere, which means (IMO) that it really doesn't matter whether your birds are carriers or not.

Resistance is a continuum. Some are more resistant, some less; some completely, and some not at all. If a bird recovers, it has partial resistance. If you're trying to breed for resistance, select the most resistant birds you can find. IMO, killing off the ones who recover is, well, not the best strategy.

Schipperkesue wrote:Ipf, I recall a previous conversation about Marek's. The ones who did not get it may have a natural immunity. What about those who get it and recover? No, I suspect?

Ones that don't get it have resistance. Ones that do and recover forever shed it.

We've had this discussion before, and I'm not going to go on about it, but do want to say:
1) Resistance isn't all or nothing - it's a gradation from no resistance to compeltely susceptible.
2) Partially resistant is better than completely susceptible.
3) All birds are exposed; the wind is a very efficient carrier. IMO, It won't significantly increase your chance of infection if you have a carrier in your flock. In fact, it can help you identify resistant birds, by "challenging" them.
4) (and ths may be the most important, from my experience) different strains of Marek's have different levels of virulence (nastiness=lethality). Having a low-virulence strain just may prevent infection by a higher virulence strain - I'm not sure if this has been demonstrated, but is consistent with my experience. I know I've lost birds to Marek's, but very few; and several have recovered. I've never culled.

I have to agree with ipf.

After my initial outbreak where I lost Winston, I haven't had much recurrence, though I have seen it on occasion in a couple birds (odd head movements). It usually only happens once or twice, like a nervous tick, but it looks very much like the 'stargazing' infected birds can exhibit.

I did some research after I had it flare up originally and found out once you have it, you'll have it forever. It can come from or get into the wild bird population and is relatively unavoidable, whether resistant birds shed the disease or not. I don't quarantine them anymore, and if I see anyone with a bit of a limp, whether its due to fighting or not, I put them in a breeding pen for a few days for a chance to heal up so I can monitor any decline if there is one.

I also read that having turkey's in with your chickens can help the matter. Mareks is a form of the herpes virus and, apparently, turkey's carry a dormant virus that can help build immunity and resistance to Mareks. Though they can't catch it from turkey's, it can lower their immune systems if they're highly susceptible. I guess its a bit of a trade off, depending how you look at it.

I won't cull for Mareks unless they cannot feed themselves or drink water.

Turkey herpes is a related virus (different species, same genus), and yes, it can confer immunity to Marek's. Whether it confers immunity to all strains (and there are a considerable number) is unclear to me; maybe someone out there has the answer. Thing is, since it's pretty much asymptomatic, how do you tell if the turkey has herpes?

ipf wrote:Thing is, since it's pretty much asymptomatic, how do you tell if the turkey has herpes?

That was my thought, however I thought, perhaps, it was something they all carried naturally? I'm likely wrong on this.

All good thoughts and I have to further this discussion with some things that I would like to point out.

Wonder how many of us have the room, time, guts or gumption to take a bird that has become partially paralyzed to recover. I know that I do not. If I see any symptoms of a bird that has become weak in such ways, if I thought it marek's generated, I cull.

I do NOT have the time, guts, nor gumption to take a bird that I think may have marek's disease and nurse it back to health. Just me. Hard core? Maybe, maybe not. Hard to say regardless.

I have a tough love. It is the same with a chick with splayed legs at birth. Encountered that two times since my beginnings with fowl. I cull. I do not have the time, guts, nor gumption to try to fix something with something wrong like this I mentioned. Just me.

I think it admirable, on the other hand, for those that have that more caring attitude and will try to fix a baby bird with bad legs. Have at it. That is a good thing. But not me, at all. Maybe that is a side of me that is just too rough, but again, that is me.

I have seen a few cases of what I believe to have been marek's here. As we all know and hear, marek's disease is everywhere and is one of the most widespread of all chicken diseases and causes the most harm to the industry, fancy, call it what you will. It is everywhere. We all know that and have read that time and time again. You cannot avoid marek's disease, it is there....everywhere....period.

As ipf says, this discussion has been gone over, over and over and over and there are many threads here, and in other places too, where others have given their thoughts, their experiences and lots of professional information has been given. But I am willing to spend some time here with this again, to me, all information is reinforcement of what I know or do not know. I like it. Bring on the discussion, I like it

In the instance where I have seen a young bird get a dropped wing and then that paralysis has continued on down, wherein the leg becomes unusable too, I cull. As I said, I do not have room to bring a bird in and nurse it. And as I said, I neither have that guts, gumption nor wish to do that.

On that other side of the coin. Guess I could have left the bird to recover. That bird may or may not have. So what then....do I sit and watch and wait to see if this bird is going to get killed by the other mass of birds that don't really give a hoot or a hollar if they run over a bird that just can't get around. I watched a youngster, one time, about the age of 12 weeks old. Not doing well, that paralyzed leg coming on. That bird tried and tried to hop up about 6 inches to get into his night house. Failure each time, with falling down in the so doing. So, what then? Just a matter of time before that bird would be trompled, laying flat on the ground, some avoiding the mass of the body, others just walking over. Nope. I cull when I see something that cannot walk any more. That to me is humane. Others it may seem barbaric. I stand by what I think. And I think that any bird that is weak in any form, does not have a place in m chicken yards. Weak birds bring bad things. In my mind, that is a closed subject. Only the strong are part of my clan here. Tough love? Yep.

I choose not to have to watch over a failing bird, in the manner in which I have seen, what I think to be, marek's manifest. Why would I want to have a bird that could have a terrible death by being overcome by others, when I can take that bird to a place where he can run again, be free to eat the bugs and grass, a happy place. I think that is where all creatures big and small go to, when the time comes...a happy place, where the body is whole again, as it was when it came into this world. My thoughts, perhaps, the good, the bad and the ugly. With that, all wishes for a wonderful day, CynthiaM.

I agree with IPF on many parts.

My own opinion from my own experience.
Theres is Mareks and there is slipped tendons. Slipped tendons can hit a bird at any age, at any time and a bird can recover from. I have had birds, several years old develope a slipped tendon where the leg can go clean round and become useless. I have heard that sometimes by simply manipulation of the leg that a slipped tendon can be popped back into place. It may cure it OR that tendon can continue to pop out resulting in the leg never being normal or even of use.

For myself, I will give a bird time to heal and recover. Honestly, I have only had 2 successes with a turned leg either from Mareks or Slipped Tendons. One the bird died just after being a year old: its weight became too much for the bird to cope and it stroked out one day. The other I found a home for it, the lady not minding it had a bum leg.

I have attempted to heal many. Both condition happen very fast, I find, and so if I see that treatment is not helping at all and the bird can no longer feed or water itself, the kindest thing to do is put it down. Starvation is not good poultry management.

Also, I have found in my experience that inbreeding can cause gentic failings, one being poor legs. In my Houdans, I am finding that these birds often develope leg problems that will show up between birth to 6 months of age. I have hatched out both Polish and Houdans and kept them in the same enviroment, fed the same food and housed together. My houdans would develope leg problems where my polish would not. I believe that the poor gene pool that exists now for some breeds may have something to do with higher number of certain defects found in said breeds. Leads me to wonder that if this might be something we who chose to raise rare to scarce breeds might have to consider when deciding to raise them?

I have to agree with those who do not wish to keep any form of weakness in their flocks, or spend time nursing along a chick that may or may not recover. Like Cynthia, I have had birds with symptoms that are quite unmistakable as being Marek's disease. The wing paralysis, then going over onto one side. These birds are culled, no matter how much I was hoping to keep them for breeding. I simply do not want a bird that has shown a weakness like this to recover and end up in a breeding group. Or continue to shed disease to youngsters each year.
I do understand the other point of view - that surviving this disease is a clear demonstration of a good immune system and are worth keeping. It is just not my choice to go that route.

Its interesting to note that (I think) every case of Mareks I've experienced in the past has been from chicks hatched out of eggs that I've bought from other breeders. Now that I think about it, I believe they were all located outside of the province. My own flocks have built up a resistance to the local strains, and I do not experience this disease in chicks from my own flocks.
However, in the spring of 2011 I sold a batch of started chicks to another farm located within 60 kms of my farm, and later found out she had Mareks issues. Birds were tested and confirmed positive, but I had no sign of it in chicks from the same hatch that I kept and raised for myself. Obviously there was a slightly different version of Marek's within that hour's drive from my farm to hers, and the chicks were susceptible.

I am now a firm believer that there is enough variation the strains Marek's in particular locations to cause symptoms of the disease to appear amongst birds that have not previously been exposed to that exact strain. Maybe that is something to be aware of for people buying hatching eggs. And I suppose for those selling hatching eggs, too. I think a person can breed for resistance and be very successful with that in your own area, but difficult to predict if chicks or eggs you sell will have the same resistance for other people in other geographic locations.

Yes, there is clear scientific documentation of multiple strains and serotypes of Mareks.

And a big yes! to the possible perils of inbreeding - leg problems, beak problems, vigour, fertility and just about anything, can be affected by inbreeding.

Having said that, some populations are very robust, having had deleterious alleles purged through many generations of carefully designed mating schemes and intensive selection (to expose, and then eliminate the presence of the deleterious alleles). In these populations inbreeding is apparently virtually without negative effect.

We bought day olds from a popular US hatchery last summer. The chicks were suppose to be vaccinated, but a couple have died recently with the symptoms as described in this post. We ordered chicks from 5 breeds. The two that died were from one breed. Does immunity decrease over time or are certain breeds more likely to develop the illness?

There are some breeds or even some lines that are more susceptible to Mareks for sure.

coopslave wrote:There are some breeds or even some lines that are more susceptible to Mareks for sure.

I agree.

ipf wrote:Yes, there is clear scientific documentation of multiple strains and serotypes of Mareks.

And a big yes! to the possible perils of inbreeding - leg problems, beak problems, vigour, fertility and just about anything, can be affected by inbreeding.

Having said that, some populations are very robust, having had deleterious alleles purged through many generations of carefully designed mating schemes and intensive selection (to expose, and then eliminate the presence of the deleterious alleles). In these populations inbreeding is apparently virtually without negative effect.

Now I have a question IPF that maybe you can answer. It's one I am sure others may have as well as I.

Does inbreeding really work or does it just mask defects within that flock? Because I have heard and read some opinions that state inbreeding only works at masking defects. That most times when outside blood is introduced that the offspring will often show defects that were otherwise hidden through inbreeding.

As well, I have also heard this from some breeders of exhibition birds. That some flocks can become so inbred that their natural resistence to some diseases, such as Merecks becomes poor. So poor in fact that even mild exposure is enough to do considerable damage to the flock.

Just saying as I do not wish to offend anyone who supports inbreeding. I am asking for my own education so that I may learn.

Some breeds (e.g. Cochins) are definitely more susceptible than others (e.g. Cochins). Also, for some reason, vaccine doesn't always "take" so one bird might be immune and another susceptible. As with people, it's never 100%, but provides good population-based immunity.

Toybarons - w.r.t. inbreeding masking defects - no, it's the other way around. Outcrossing masks defects, while careful (and I mean REALLY careful) inbreeding can expose them, and so facilitates selection to eventually remove the deleterious alleles.

Outcrossing generally results in robust, vigorous, cheerful and productive birds, but if you are focussed on SOPs, they probably won't do it for you.

I agree totally with your para "As well, I have also heard this from some breeders of exhibition birds. That some flocks can become so inbred that their natural resistence to some diseases, such as Merecks becomes poor. So poor in fact that even mild exposure is enough to do considerable damage to the flock."

IMO, inbreeeding (including linebreeding and all other synonyms) without an understanding of what you're doing is a Really Bad Idea. Some breeders have that understanding, some not.

ipf wrote:Toybarons - w.r.t. inbreeding masking defects - no, it's the other way around. Outcrossing masks defects, while careful (and I mean REALLY careful) inbreeding can expose them, and so facilitates selection to eventually remove the deleterious alleles.

Outcrossing generally results in robust, vigorous, cheerful and productive birds, but if you are focussed on SOPs, they probably won't do it for you.

I agree totally with your para "As well, I have also heard this from some breeders of exhibition birds. That some flocks can become so inbred that their natural resistence to some diseases, such as Merecks becomes poor. So poor in fact that even mild exposure is enough to do considerable damage to the flock."

IMO, inbreeeding (including linebreeding and all other synonyms) without an understanding of what you're doing is a Really Bad Idea. Some breeders have that understanding, some not.

Thanks for the answer IPF. Appreciate it.

Wow, careless editing, sorry!
I mean that Cochins are an example of a breed that is more susceptible to Marek's than others. . .

Although we have Cochins from the order, the breed in question is the white laced red Cornish (I hope I got the colour order correct). Just to go a bit farther, we ordered 5 Black Cochins, but 2 were DOA (within 24 hours). We lost a third due to a known cause.

Mareks doesn't kill that quickly - more likely the stress of transport of even just delayed manifestation of congenital defects.
I haven't heard that the WRLCs are more susceptible to Marek's - but that doesn't mean they arent. It will also vary from strain to strain. . .. so complicated.

So IPF are you saying that marek's is like Coccidious(sp?). That all chickens in a way have it and have built up immuinty by exposure?

If so i agree with you that, culling would not help the situation. With Coccidious from the reading i have done, is something that allways lives in the Chicken. Only effecting/harming the chicken when it get's to very high levels. Thus all chickens have some immuinity to it, but others will be more sectable to it.

I am all for culling something i know it will not be a benfit to me in anyway.