I don't know about Canadian laws but private reputable breeders and USA hatcheries here can vaccinate for Marek's ~ with my local breeder it is standard. And spread of vaccine infections don't happen with safety measures and separation/quarantine of vaccinated chicks ~ vaccinated 1-day old chicks are shipped from USA hatcheries when a customer requests vaccinated chicks.
Authorities would be down all over breeders or hatcheries if they weren't certified here. And as always good breeders and hatcheries recommend separation/quarantine at least for 1 month for illness observation before integrating new chicks/birds into existing flocks. We personally keep our new birds separated at least 2-3 months before mingling.
With a limit of 5 hens/no roos we have the luxury of being extra solicitous "helicopter" chicken parents in watching quarantined new birds. Years ago on my folks farm (1940's) there wasn't the proximity of farm flocks to spread infection but in this crowded world of chicken owners and industrial poultry businesses with billions of chickens worldwide it's a whole different environment for disease spread today and I'm personally grateful for vaccinations.
A more spreadable chicken vaccination IMO is the live fowl pox virus under-wing scratch. Reminds me of the 1950's live polio scratch vaccines they gave us school kids. It wasn't till decades later a dead polio virus developed. Ah! We older generation kids were the guinea pigs of govt-mandated experiments!
Tx ~ CROOKED WATTLES WEDNESDAY
Uneven as a juvenile and still uneven now
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