Vaccinations make a bird contagious?

Discussion in 'Emergencies / Diseases / Injuries and Cures' started by maddogdodge, Sep 4, 2014.

  1. maddogdodge

    maddogdodge Songster

    Apr 27, 2014
    I have a flock of 11 birds of different ages and backgrounds. Some are pure breed chicks from a breeder that have been vaccinated for Merricks. Some are cross breeds from the local school, I doubt they've been vaccinated. And some are from unknown background, so I don't know if they're vaccinated or not...

    I was planning to buy some ex chicken farm hens in the next week, however when I spoke to the lady about introducing them to my flock, she said that hers are vaccinated and if mine aren't then mine could catch the disease from the new ones... Is this true? What disease would that be?

    I'm really annoyed now because if this is true then that really puts a block in the middle of my plans.

    Say this is true and poses a huge risk for my current chickens... Am I able to get my chooks that i'm unsure as to whether they are vaccinated or not, vaccinated?

    I did a bit of reading and I read somewhere that Merricks is not contagious from a vaccinated chook to an unvaccinated chook, Is this correct? And if so, then what would be the disease that the chicken farmer is talking about?

    Thanks in advance for any info people have [​IMG]
  2. Wyandottes7

    Wyandottes7 Crowing

    Jul 24, 2013
    Some vaccines, for some diseases, do make chickens carriers of that disease. They can then spread the disease to other birds. For example, I believe that a vaccine for Laryngotracheitis makes chickens carriers. But, there are other Laryngotracheitis vaccines that don't make them carriers.

    The Marek's Vaccine does not make chickens carriers of Mareks, as it the vaccine is made of a turkey virus which doesn't affect chickens, but builds immunity to the real Marek's Disease.

    I'm not exactly sure which disease the chicken farmer was talking about. It could be Laryngotracheitis, or another disease. Maybe you could ask her? She may just be misinformed, and you can still get chickens from her.
    Last edited: Sep 4, 2014
  3. Ridgerunner

    Ridgerunner Free Ranging

    Feb 2, 2009
    Southeast Louisiana
    Mycoplasma gallisepticum is the only one I’m aware of where a vaccinated chicken becomes a carrier but there may be others. You probably should ask her what specific vaccinations she is talking about. That’s better than speculating.

    They use turkey Marek’s to vaccinate chickens against chicken Marek’s. The turkey Marek’s does not prevent the chickens from getting chicken Marek’s but it does stop the lesions that cause the damage from forming. Vaccinating them with turkey Marek’s virus does not make them carriers of turkey Marek’s unfortunately. They cannot pass that protection on to other chickens.

    Chickens vaccinated with turkey Marek’s can still get chicken Marek’s and can still pass that disease on to other chickens, but the vaccination does not make them carriers. The infection would have to come from some other place. I know I’m repeating myself but I’m trying to be clear.

    I suggest you also talk to that breeder that has vaccinated chicks for Marek’s. Why are they vaccinating them? Do they know they have Marek’s in their flock or are they just vaccinating as a general precaution. If they have Marek’s in their flock those chicks are carriers unless they have been totally isolated from the flock. Marek’s is not passed down through the eggs but is generally spread by air or direct contact. Chickens give off a lot of dander which can travel long distances in the air. It would take serious isolation to be sure the chicks are not carriers if the breeder has Marek’s in the flock.

    I don’t know if the breeder has Marek’s or not. That’s why you need to speak to them directly. I don’t know specifically why they choose to vaccinate.

    Like you, I don’t know the background of the chickens with unknown background. Any time you introduce living chickens you take the chance of introducing some disease or parasite. People do it all the time and it is usually not a big problem but occasionally flocks are totally wiped out by introduced chickens. Flocks can develop flock immunities to certain diseases. They may be carriers but since they have developed immunity they are not going to show any symptoms. Your existing chickens could be the carriers just as easily as the new chickens. Coccidiosis is a great example but there are more serious diseases that could be the problem.

    A standard way to provide some protection when mixing in new animals is to use quarantine. Isolate the new chickens for about a month. The better the isolation the better the quarantine. Marek’s is not the only disease that can spread by air. Don’t wear the same shoes when working with the different flocks and don’t spread any diseases by using the same feed or water buckets. Really isolate them.

    This should protect you against most diseases the new chickens have come into contact with recently. The idea is that within a month they should show visible signs of infection. It’s also a good time to treat for parasites like mites, lice, or worms.

    The stress of moving and quarantine may drop their immune system enough to show symptoms of any diseases they have a flock immunity to but probably not. To protect against the diseases they have flock immunity to I suggest taking a potentially sacrificial member of your current flock and put that chicken with the new ones. If it gets sick, then they are carriers. If they get sick then your flock is the carrier.

    As I said, people do this all the time, people that show chickens or that go to chicken swaps for example. Occasionally there are serious problems but many people don’t experience them. No one can deny there are risks but no one can guarantee you will have a problem either.

    Good luck!
    1 person likes this.
  4. maddogdodge

    maddogdodge Songster

    Apr 27, 2014
    Thank you both for your awesome responses, very informative, I really appreciate it! [​IMG] I'll have to give the farmer a call and find out what her chickens are vaccinated for, I've noticed the most common one seems to me Mareks, so hopefully its that, then I won't have a problem.

    The breeder I got the chicks from just vaccinates as a precaution, they don't have Mareks in their flocks.
  5. Nambroth

    Nambroth Fud Lady

    Apr 7, 2011
    Western NY
    My Coop
    Your safest bet is to find out exactly what they were vaccinated for. Then we can answer this properly. Some vaccinations, such as Marek's, does not cause the chicken to be carriers (unless they were exposed to Marek's, then any exposed chicken is a carrier). Some vaccinations, such as the one for “Infectious Laryngotracheitis (ILT) WILL cause the chickens to be carriers. So knowing exactly what they have been vaccinated against is very important.

    Use a lot of care in bringing in birds to your flock. Always do a strict quarantine of at least 30 days (60 is ideal but I know it might not be realistic for most people) and watch very, very carefully for any problems. Birds can be "silent carriers" of many diseases, sadly.

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