You dont have to vaccinate, but I know many recommend it. I'm not sure what age. Hopefully, someone who knows more about vaccinations can help us here.
If it were me, I would, because the scabs that fell off of these birds will harbour the virus a long time and chances are the mosquitos that fed on these birds are less than a hundred yards away..Pox vaccine given to chicks under 6 weeks usually doesn't give life long immunity,but it will protect them till a booster is given.
Its possible the chicks may never catch it, But why take the chance when i'ts so easily prevented..Oh and Hello Cynthia