I currently have 7 chicks (some 5 weeks old, a few 6 weeks) bought from a local breeder/farmer. Quite certain they aren't vaccinated for anything. Should I look into vaccinations (marek's and such) or is it of any use at this stage? Also, I'm upgrading my coop to a (relatively) large coop (to be able to more than double my flock size); and definitely want more chickens. Two part question here: First, since mine are currently not vaccinated, how should I go about incorporating new birds? What should I look for in a quarantine outside of the obvious signs of disease and illness? Secondly, how best to incorporate chickens of different ages (ie, if my current 6 week old chickens are 12 weeks old, how old do new chicks need to be before they can be housed together?) Along the same lines of not being vaccinated; are hatcheries really the best option for adding new birds? Unfortunate if so, seeing as the 'quality' of birds can evidently be relatively low from the major hatcheries...