my 150 chicks that I am raising are doing so good only lost 5 of the hatchery bird which out of 150 I think is good....I have more that I picked up from breeders that are doing great too have not lost any of them...I take very good care of them change their water 4 times a day and feed them constantly....anyway what I am asking is I have had a problem here with CRD...have not lost a bird though but culled them....I have 11 grown laying hens which are very healthy.....with these baby chicks I have read you can give a poulvac vaccine at 8 weeks....should I do that with these chicks or not?....I want them all to be healthy....