Before you make the decision to vaccinate any bird for MD, please view this:
https://www.pbs.org/newshour/science/tthis-chicken-vaccine-makes-virus-dangerous
Something to consider:
The MD vaccine a live vaccine. It does not kill the MD virus. Your birds can still get MD if they have been vaccinated, but they may not be killed by the MDV. They will be carriers, and can then infect any unvaccinated birds.
The MD vaccine is a leaky vaccine, which means that it does not kill the disease. The resulting virus will then mutate to become a much more lethal form. This has already been seen in many flocks, including flocks of BYC members. A recent thread: Lady got vaccinated chicks from a hatchery. One by one, they died of Marek's. She's left with the decision to cull yet an other chick who is showing all of the classic signs of MD.
Turkeys carry a less lethal form of MD. I encourage wild turkeys to visit my yard b/c of the possibility that they will shed the MD virus as they pass through my yard. This will activate my bird's immune response to Marek's disease virus.
I feel so strongly about the MD vaccine that: If someone were to offer me free day old
VACCINATED chicks from a reputable hatchery or breeder that were on my "must have" list...
I would absolutely decline them. I will not bring any birds onto my property IF they have been vaccinated for MD.
Other considerations, since as ES4L pointed out, MD virus is very common, yet not all birds are infected or symptomatic, I am of the opinion that it's the birds with compromised immune systems that succumb to MD. That leads me to the conclusion that I should do everything in my power to ensure that my birds have a strong immune system, starting before the eggs that will hatch ever get laid!
1. Put breeding flock on good protein diet, and extra multivits several weeks before hatching eggs.
2. Provide optimum hatching environment, whether it's broody or incubator. If incubating, take the time to read "hatching eggs 101" before ever plugging in an incubator.
3. Got chicks? Give them Poultry Nutri Drench for the first 2 weeks. After they are eating crumble, give them a scoop of soil or a plug of sod from your untreated lawn/garden. This will load their guts with beneficial bacteria and fungi for improved digestion AND IMMUNITY.
4. Got birds in coop/run? After they've destroyed the sod, convert your run to deep litter style. They will reap great reward b/c of the beneficial bacteria and fungi that will populate their guts for improved digestion AND IMMUNITY. Those beneficial micro-organisms will also help to destroy the pathogens in the soil.
5. Wanna lower your feed bill while improving your flock's digestion and immunity? Give them fermented feed.
I will not give my chicks medicated feed. (Amprolium is a Thiamine blocker.) I've never used medicated feed, and have never had coccidiosis in my flock. The use of medicated feed is a personal decision. Do your homework, and make your own personal decision regarding medicated feed instead of just choosing to use it or not use it based on what others claim is the right thing to do. Again, I choose early exposure to cocci by giving soil from my yard during the 2 week window after hatch when the chick has her strongest immunities provided by her mother.
6. Stress reduction: Provide enough space. There is a reason why 4 s.f. in coop and 10 s.f. in run is considered the bare minimal amount of space for a back yard flock. Crowded birds are stressed birds. This shows up as flock aggression, feather picking, and can lead up to blood shed and cannibalism.
Your coop also must be well ventilated year round, even in the winter when temps are below 0*F. Start with 1 s.f. per bird or an area = to 10% of coop floor space. Birds have sensitive respiratory systems. ANY ammonia in the coop (by product of poop) can burn their lung tissue.
7. A very unpopular statement: cull weak birds from your flock. It's commonly stated that 10% of the flock or herd carry 90% of the disease/parasites. Remove the weak members from your flock, and the remaining flock members will be stronger. Over time, such management can result in a flock that is much less likely to succumb to disease. IMO, this is how we should be "managing" the threat of MD or any other illness.
LG, I seen and decided to follow this thread. Since I have no knowledge in this matter , I held back any advice
