I have 2 chickens (polish crested & buff orpington) that are about 18 weeks old. They are not laying yet. I have 3 chicks (barred rock) that are about 7 weeks old any only have a few "baby" feathers around the neck area left. The chickens have all free ranged together without any problem and I want to mix them so that the chicks get out of the box in the garage. My issue is food. I can't get flock raiser at my local store. I have chicken crumble and medicated chick food (purina). How do I feed them so they can live together in the coop?