I would like to integrate my younger chicks, ages 12 and 16 weeks into the main flock. My question is, my older chickens are on layena and the younger ones, flock raiser. I do not want to change the older chickens food...is is safe at these ages to allow the younger chicks to eat the layena? I don't have a smaller coop setup so these chicks are still in my house!!! Help!