I vaccinated my new chicks against fowl pox since my big chickens had it. They were just a few days old and 4 were about 6 weeks old. I have heard I need to repeat the vaccine at 12 weeks with an "adult" vaccine (Chik-n-Pox vs. Poxine). I don't have easy access to vaccine so I wonder if this is true and if it is if I can wait until my small chicks are 12 weeks which would put my 4 past the 12 week age. Has anyone had experience with this?