I would like to add 2 more to my flock, but my worry is I did not know they needed to be vaccinated and there for my girls were not, now there 20 weeks old and I fear if I add even chicks to my flock my girls may get sick. If I get vaccinated chicks from people around my neck of the woods, will my girls be safe from mercks disease or am I taking a chance? We gave away a rooster and have more room for 2 more birds comfortably, I would also like to get older pullets already vaccinated instead of chicks. Is this ok, or should I just forget it since my birds were not vaccinated am I taking to big a risk? We love our girls,