I have 10 laying hens, 1 pullet near POL and 5 chicks that are now 12 weeks old. I got them at 8 weeks old. After a quarantine period I put them out in a small pen where the big girls could see them, I'm assuming like you have. After a couple days I supervised short visits with the big girls, then longer and longer. I have lots of places for the chicks to hide, run around, under etc to get away if they are getting picked on. And they will get picked on. From what I can tell it sounds worse than it is. The chicks squeal and run if a big hen just gets too close. I think the hiding places are very important for the chicks. For the last week everyone has been together day and night. The little ones put themselves to bed in the big coop without being caught and stuffed in (I did have to do that for 2 nights). There is a bit of squawking and squealing as everyone tries to find that perfect roost for the night though but in the morning it seems to have all been worked out with no blood or loss of feathers.
After reading this thread, I am feeding Flock raiser to everyone with oyster shells on the side. When the small ones get to be older (not sure what age I will determine that to be) I will switch to layer feed. Everyone gets scratch, grit, greens and can roam my grassy yard all day. I have multiple feeders and waterers around so everyone gets a chance to eat/drink in peace. I hope this helps. There is SO much to learn and mistakes to be made. This website has been an invaluable source of information for me in the last 1.5 yrs.
