I have always try to have my chicks hatched out around the first of March so I could start growing them out on the early Tennessee green spring grass and bugs. But if chicks hatched out in December & January produces larger birds I will change my hatching dates and start hatching out much early than I have in the past.
One thing I feel I must do is hold off on hatching anything next spring. If I wait until next December to start hatching all the pullets & pullet chicks that I have this year will be hens laying much larger eggs.