Hi! About ten days ago I bought two pullets from a farm. The lady who sold them to me told me they weren't Mareks vaccinated, but they were already immunized because they lived with her turkey. My 4 other girls were all vaccinated as chicks. Should I vaccinate the 2 new girls, or is the "turkey immunity" real? I'm asking here because I've never heard of that... Also, the girls are about 4.5 months old... Is it too late to vaccinate? Thanks in advance!