I have 3 pullets (Easter Egger, Buff Orpington, and Speckled Sussex) that will be 18 weeks old on December 7th. According to the starter/grower I have them on, they are due to change to layer feed around that time. I am not planning on having artificial light in the coop, and I live in North NJ. Should I switch them to layer feed, even if I doubt they'll be laying eggs until spring? I never had chickens before, but I am thoroughly enjoying them! Thanks for any advice.